One-dimensional Transfer Research Articles

Failure and reinforcement of reservoir landslides: Insights from centrifuge modeling and numerical modeling

The construction of the Three Gorges Reservoir dam in China has led to an increase in reservoir landslide events. To mitigate these geohazards, multiple rows of stabilizing piles (MRSP) have been employed to stabilize massive reservoir landslides. This study utilizes centrifuge and numerical modeling to investigate the behavior of unreinforced landslides and MRSP-reinforced landslides in reservoir areas. The failure mechanisms of unreinforced landslides, as well as the mechanical behavior and stabilizing mechanisms of MRSP under reservoir water level (RWL) fluctuations, are examined. The results indicate that elevated downward seepage forces contribute to pre-failure sliding, but are not the sole cause of catastrophic failure. Instead, rapid pre-failure sliding leads to soil particle compression and crushing in the saturated sliding zone, resulting in excess pore water pressure and accelerated overall failure. This excess pore water pressure-dependent mechanism explains the observed “step-like” deformation pattern and rapid failure pattern in reservoir landslides. Furthermore, the study reveals the formation of soil arches between adjacent MRSP groups, causing stress concentration on boundary columns and necessitating reinforcement. The finding challenges traditional one-dimensional load transfer ratios, advocating for a two-dimensional approach that accounts for variations across rows and columns. Notably, the study also highlights significant variations in load transfer laws within MRSP under different RWL operations, emphasizing the need for a more nuanced understanding of MRSP behavior.

Unified, Integral Approach to Modeling and Design of High-Pressure Pipelines: Assessment of Various Flow and Temperature Models for Supercritical Fluids

Abstract A unified one-dimensional, steady-state flow and heat transfer model is presented for the pipeline transport of fluids at high pressures, including the supercritical conditions. The model includes a generalized temperature equation, presented here for the first time, and accounts for all of the important effects, including the property variation, viscous dissipation, Joule-Thomson (J-T) cooling, and heat exchange with the surrounding. With appropriate approximations, this model can yield all isothermal and non-isothermal pipe flow solutions reported thus far. A generalized multi-zone integral method is developed which solves the two resulting algebraic equations for pressure and temperature in conjunction with a property database, such as the National Institute of Standard and Technology (NIST) Reference Fluid Thermodynamic and Transport Properties (REFPROP). With appropriately selected number and size of the zones and using property values at the mean temperature and pressure within each zone, this integral method can accurately predict the complex effects of the governing parameters, such as the pipe diameter and length, inlet and exit pressures, mass flow rate, J-T cooling, and inlet and surrounding temperatures. Its accuracy for small-to-large diameter pipes has been ascertained by a comparison with the numerical solutions of the differential form of governing equations that requires a large number of small grids along the pipe and the values of mean properties within each grid. Indeed, this integral model can be used for the pipeline transport at both subcritical and supercritical pressures as long as the fluid does not encounter its anomalous states and the phase-change.

Mathematical modeling and experiments on the acoustic properties of a frame structure with a membrane

This study is a fundamental work conducted to theoretically estimate the acoustic properties of a simplified frame structure, that is, a simplified foam sound absorbing material, which is a porous material. The changes in the sound absorption characteristics caused by the presence of a membrane are also considered as part of the fundamental study of foam materials. In the mathematical model, the clearance composed by the frame structure with the membrane is divided into elements perpendicular to the direction of the soundwave incidence and approximated as a clearance bounded by two parallel planes. The characteristic impedance and the propagation constant are obtained for the approximated clearance and introduced into a one-dimensional transfer matrix. The transfer matrix method is used to calculate the sound absorption coefficient. The calculated theoretical values are compared with the experimental values. Sensitivity analysis is also performed for the changes in the parameters used in the theoretical analysis, such as the cylinder diameter and the pitch between the cylinders. The samples are fabricated using a three-dimensional printer. The sound absorption coefficient is measured using a two-microphone impedance measurement tube. The theoretical values based on the analysis tended to be close to the experimental ones. They showed a high prediction accuracy with respect to the peak frequency of the sound absorption curve. These values for the presence and increase of the membrane closely followed the experimental values when the percentage of the membrane present was varied.

Extraordinary thermal conductivity for carbon nanotube encapsulated linear carbon chain

Carbyne is a sp1 linear carbon chain (LCC) with characteristics of strong chemical reactivity and extreme instability under environmental conditions, which has become an obstacle to the application of LCC with high thermal and electrical conductivity. Utilizing CNT as a container to store LCC is one of the most feasible ways to realize LCC applications. However, current research of LCC encapsulated in CNT (LCC@CNT) focuses on its preparation and lacks of in-depth exploration of the intrinsic heat transfer mechanism. This paper reports the high axis thermal conductivity of LCC@CNT, explore the thermal transport enhancement degree of LCC@CNT under a wide temperature range and multiple diameters, and analyzed the underling mechanism through crucial thermal parameters and phonon theory. When LCC is loaded in CNT, the axial thermal conductivity of CNT is further increased by 15 %. Moreover, LCC@CNT shows the lower sensitivity diameter than pristine CNT. This work is expected to provide data support for the application of LCC, the lower production standard of CNT, and also attempt the higher efficient one-dimensional thermal energy transfer micro devices.

Experimental and theoretical basic research on sound absorption characteristics of foam materials with and without membrane

A basic study was conducted to theoretically estimate the acoustic properties of a sound-absorbing foam material. Generally, the lattice of sound-absorbing foam materials contains membranes. Herein, for simplicity, a mathematical model was constructed assuming a cubic frame structure as the basic frame structure of the foam, which included a membrane. Accordingly, the sound absorption coefficient was obtained and compared with the experimental results. In the mathematical model, the clearance in the frame structure (with membrane) was divided into elements and was approximated as a clearance surrounded by two parallel planes, considering the exact shape of each element. Herein, the characteristic impedance and propagation constant of the approximated clearance were obtained and treated as a one-dimensional transfer matrix, and the sound absorption coefficient was calculated using the transfer matrix method. For the experiments, the samples were fabricated using a 3D printer and the sound absorption coefficient was measured using a two-microphone impedance tube. Overall, the experimental and theoretical results exhibited similar trends.

Intermittent fault diagnosis of analog circuit based on enhanced one-dimensional vision transformer and transfer learning strategy

As the major cause of false alarms in built-in test (BIT) system, intermittent faults of analog circuits may trigger abnormal equipment shutdown and lead to catastrophic accidents. With complete randomness and great non-repeatability, intermittent faults are arduous to be detected. To enhance the reliability and safety of electronic systems, an end-to-end approach based on enhanced one-dimensional Vision Transformer (1DViT) is proposed to realize intelligent diagnosis for intermittent faults of analog circuits. The signal anomaly caused by intermittent faults can be regarded as a kind of random anomaly from global perspective, and there are also rich local feature information in the fault interval. Completely composed of self-attention mechanism, Vision Transformer possesses prominent performance on extracting global features and modelling global representations, thus can be applied to identify intermittent faults. Meanwhile, to further enrich the feature representation, one multi-scale convolution fusion module (MSC) incorporating a series of convolution operations is designed and combined with 1DViT to extract and fuse the valuable local information. However, in practical test, due to the complex operation process, it is cumbersome to collect sufficient fault data to guarantee the effective training of the proposed model. To cope with this problem, transfer learning strategy is introduced. The model will be first pre-trained with adequate simulation data which is easily accessible, and then fine-tuned with a relatively small amount of actual fault data to help match the practical feature distribution. Experiments on two typical circuits demonstrate that the proposed method could achieve excellent diagnostic result in practical test.

Mathematical modeling and simulation of oxygen mass transfer in rotating biological contactor (RBC) for bacterial cellulose production

The Rotary Biological Contact (RBC) reactor has a unique aeration system that provides a moving bed for easy and efficient oxygen transfer within the system to overcome the limitations of stationary culture in bacterial cellulose (BC) production. In most cases, oxygen mass transfer is the limiting factor of an aerobic process, hence the changes in the oxygen mass transfer coefficient within the system have been given special attention. In this study, the RBC bioreactor producing BC was modeled based on one-dimensional oxygen mass transfer in the direction perpendicular to the surface of the discs. The Monod kinetic model has been used to express cell growth. Simulation of the mathematical model was done based on the numerical solution with finite difference method in MATLAB software. Sensitivity analysis was performed to investigate the effect of changing different system parameters in RBC modeling. The simulation results showed that with the increase in angular velocity, the oxygen transfer coefficient and subsequently the mass transfer rate increase. Also, at a certain angular velocity, the oxygen mass transfer coefficient increases with the increase of immersion depth. The best disk rotation speed considering other parameters as well as the laboratory results was 13 rpm with a 45% indentation percentage and the optimal distance between the disks was 1.5 cm.

An estimation of temperature in living tissue using a fractional model with sinusoidal heat flux conditions on the skin surface

An accurate and quantitative description of the thermal responses of skin tissue under sinusoidal heat flux conditions on the skin surface is provided in this study using a fractional model of the bioheat transfer equation. The governing fractional one-dimensional bio-heat transfer equation was transformed into a dimensionless form to get closed solution by the Caputo-Fabrizio time-fractional derivative technique. The proposed technique, with the aid of symbolic computation, provides an impressive solution for the bioheat transfer equation. Numerical simulations were performed with the aid of Mathcad software to study the behavior of temperature transients on the skin surface exposed to instantaneous surface heating. To investigate the thermal impacts of various control factors on tissue temperature, sensitivity analysis is carried out. We found that the effects of the fractional derivative and the moving heat source velocity on the temperature of the tissue and thermal injuries are enormous, and are shown graphically for an explicit and detail discussion. Observations from the graphical representation of results, show clearly that increasing pressure term leads to increase in velocity distribution of temperature and the effect is maximum towards the center in most cases. The study reveals that bio-thermal research can help with skin burn evaluation, clinical thermal treatment equipment design, and thermal protection from various risks of skin heat injuries. In conclusion, the results of this investigation will be very helpful and useful to both clinical-therapeutic applications and medical sciences.

Pressurized Liquid Extraction (PLE) in an Intermittent Process as an Alternative for Obtaining Passion Fruit (Passiflora edulis) Leaf Hydroalcoholic Extract (Tincture)

Tinctures are medicinal plant extracts obtained by extraction with a hydroalcoholic solution (70%) by percolation (PER). This process takes about 26 h to prepare, in addition to using a large amount of solvent. In our research, passion fruit leaf tinctures were obtained using extract with the same pressurized hydroalcoholic solution as in an intermittent process. The objective was to demonstrate that this emerging technology can be economical and profitable. An optimization using Central Composite Rotatable Design (CCRD) was performed to evaluate the influence of process variables on the yields and compositions of the extracts. The temperature (T) was the factor that most influenced the responses. Extraction with pressurized liquid (PLE) provided total yields and total phenolic and flavonoid contents in greater amounts than PER. The optimized conditions of the process variables studied in the CCRD for the highest content of total phenolics (43.2 mg GAE/g) and flavonoids (58.8 mg QE/g) were at 100 °C with a rinse volume of 120% of the divided extractor volume in four cycles of the intermittent process. When adjusting the PLE in an intermittent process, and according to the one-dimensional mass transfer by the continuous diffusion of the Fick model, the effective diffusion coefficient (1.28 × 10−12 m2/s) was not affected by T. The kinetic curve of PLE extraction indicates that the adjusted intermittent process occurred in the period of the constant extraction rate when compared to the kinetics of the semi-continuous process. The yielded extracts were rich in isovitexin, and the highest levels were identified in the extracts obtained via PLE, indicating that this intermittent process can bring a product to market with the same quality but with a much shorter production time and the use of fewer solvents. Antioxidant activity, determined by DPPH, FRAP and ORAC, was also higher in extracts obtained via PLE.

Numerical simulation of burn injuries with temperature-dependent thermal conductivity and metabolism under different surface heat sources

In the present paper, the phenomena of heat transport inside human forearm tissue are studied through a one-dimensional nonlinear bioheat transfer model under the influence of various boundary and interface conditions. In this study, we considered temperature-dependent thermal conductivity and metabolic heat to predict temperature distribution inside the forearm tissue. We have studied the temperature distribution inside inner tissue and bone because it has been found that burn injuries are mostly affected by layer thickness. The temperature distribution inside human forearm tissue is analyzed using the finite difference and bvp4c numerical techniques. To examine the accuracy of present numerical code, we compare the obtained numerical result with the exact analytical result in a specific case and find an excellent agreement with the exact results. We also validated our present numerical code with a hybrid scheme based on Runge-Kutta (4,5) and finite difference technique and found it in good compliance. From the obtained results, we observed that the homogeneous heat flux has a greater impact on the temperature at the outer surface of the skin, but the sinusoidal heat flux has a greater impact on the temperature of the subcutaneous layer and inner tissue. It is found that there is no burn injury in the first type of heat source (Tw=44°C), but it may occur in the second and third types of heat sources. It has been observed that by raising the blood perfusion rate and reducing the values of reference metabolic heat, coefficient of thermal conductivity, and heat fluxes, we can manage and reduce burn injuries and achieve hyperthermia temperature.

Two-stage melting of an intercomponent Potts long-range order in two dimensions

The interplay of topology and competing interactions can induce enriched phases and phase transitions at finite temperatures. We consider a weakly coupled two-dimensional hexatic-nematic XY model with a relative ${Z}_{3}$ Potts degrees of freedom, and apply the matrix product state method to solve this model rigorously. Since the partition function is expressed as a product of two-legged one-dimensional transfer matrix operator, an entanglement entropy of the eigenstate corresponding to the maximal eigenvalue of this transfer operator can be used as a stringent criterion to determine various phase transitions precisely. At low temperatures, the intercomponent ${Z}_{3}$ Potts long-range order (LRO) exists, indicating that the hexatic and nematic fields are locked together and their respective vortices exhibit quasi-LRO. In the hexatic regime, below the BKT transition of the hexatic vortices, the intercomponent ${Z}_{3}$ Potts LRO appears, accompanying the binding of nematic vortices. In the nematic regime, however, the intercomponent ${Z}_{3}$ Potts LRO undergoes a two-stage melting process. An intermediate Potts liquid phase emerges between the Potts ordered and disordered phases, characterized by an algebraic correlation with formation of charge-neutral pairs of both hexatic and nematic vortices. These two-stage phase transitions are associated with the proliferation of the domain walls and vortices of the relative ${Z}_{3}$ Potts variable, respectively. Our results thus provide a prototype example of two-stage melting of a two-dimensional LRO driven by multiple topological defects.

A family of inverse characteristics methods

Introduction. The main idea of the grid-characteristic method is to take into account the characteristic properties, systems of hyperbolic equations, and the finite velocity of propagation of perturbations in the simulated media.Materials and methods. The simplest hyperbolic equation is a one-dimensional linear transfer equation. To increase the order of approximation of the grid-characteristic scheme to the second, you can use the Bim-Warming scheme. If we use a four-point pattern, we get a central Lax-Vendroff scheme. Difference schemes for the linear transfer equation can be obtained using the method of indefinite coefficients.Results. The grid-characteristic scheme admits a conservative variant, which is relevant if there are discontinuities (shock waves, shock waves) inside the integration domain, while the original system of equations for a matrix with constant coefficients, in partial derivatives, should be presented in a divergent form.Discussion and conclusions. When numerically solving a three-dimensional problem, the construction is performed similarly, in the case of upper and lower bounds, after scalar multiplication of the scheme by eigenvectors, relations approximating the compatibility conditions with the first order of accuracy are obtained.

ResNetKhib: a novel cell type-specific tool for predicting lysine 2-hydroxyisobutylation sites via transfer learning.

Lysine 2-hydroxyisobutylation (Khib), which was first reported in 2014, has been shown to play vital roles in a myriad of biological processes including gene transcription, regulation of chromatin functions, purine metabolism, pentose phosphate pathway and glycolysis/gluconeogenesis. Identification of Khib sites in protein substrates represents an initial but crucial step in elucidating the molecular mechanisms underlying protein 2-hydroxyisobutylation. Experimental identification of Khib sites mainly depends on the combination of liquid chromatography and mass spectrometry. However, experimental approaches for identifying Khib sites are often time-consuming and expensive compared with computational approaches. Previous studies have shown that Khib sites may have distinct characteristics for different cell types of the same species. Several tools have been developed to identify Khib sites, which exhibit high diversity in their algorithms, encoding schemes and feature selection techniques. However, to date, there are no tools designed for predicting cell type-specific Khib sites. Therefore, it is highly desirable to develop an effective predictor for cell type-specific Khib site prediction. Inspired by the residual connection of ResNet, we develop a deep learning-based approach, termed ResNetKhib, which leverages both the one-dimensional convolution and transfer learning to enable and improve the prediction of cell type-specific 2-hydroxyisobutylation sites. ResNetKhib is capable of predicting Khib sites for four human cell types, mouse liver cell and three rice cell types. Its performance is benchmarked against the commonly used random forest (RF) predictor on both 10-fold cross-validation and independent tests. The results show that ResNetKhib achieves the area under the receiver operating characteristic curve values ranging from 0.807 to 0.901, depending on the cell type and species, which performs better than RF-based predictors and other currently available Khib site prediction tools. We also implement an online web server of the proposed ResNetKhib algorithm together with all the curated datasets and trained model for the wider research community to use, which is publicly accessible at https://resnetkhib.erc.monash.edu/.

Mathematical Model for Estimating the Sound Absorption Coefficient in Grid Network Structures.

Although grid network structures are often not necessarily intended to absorb sound, the gaps between the rods that make up the grid network are expected to have a sound absorption effect. In this study, the one-dimensional transfer matrix method was used to develop a simple mathematical model for accurately estimating the sound absorption coefficient of a grid network structure. The gaps in the grid network structure were approximated as the clearance between two parallel planes, and analysis units were derived to consider the exact geometry of the layers. The characteristic impedance and propagation constant were determined for the approximated gaps and treated as a one-dimensional transfer matrix. The transfer matrix obtained for each layer was used to calculate the sound absorption coefficient. The samples were fabricated from light-curing resin by using a Form2 3D printer from Formlabs. The measurement results showed that a sound absorption coefficient of 0.81 was obtained at the peak when seven layers were stacked. A sensitivity analysis was carried out to investigate the influence of the rod diameter and pitch. The simulated values tended to be close to the experimental values. The above results indicate that the mathematical model used to calculate the sound absorption coefficient is sufficiently accurate to predict the sound absorption coefficient for practical application.

Zašto skrenuti s puta - obrazovanje i putovanje

Different educational paradigms are often represented by the same metaphor: the metaphor of a journey. In the first part of the paper, typical examples of equating education with traveling are presented and the underlying reasons for their connection are reconstructed. Then, the metaphor of wandering is contrasted with that of traveling - precisely to highlight its overlooked, forgotten, or neglected, but at least equally valuable educational potential. Finally, it is suggested to abandon the vision of a predefined set of values that education represents, in favour of opening up the possibilities offered by the diversity of its paths. Through a critical analysis of the understanding of the journeys of Odysseus, Rousseau's Emile, and Robinson Crusoe, as analogues of educational adventures, it is shown that it is neither advisable nor fruitful to uncritically adopt and follow a pattern where the beginning of education (the point of departure) and its goal (the point of arrival or destination) are strictly predefined, especially if it entails the exclusion of any deviation from the trajectory connecting the "origin" and "destination". Inspiration and a kind of code for an alternative model of educational procedure, which would avoid the shortcomings of its understanding as a more or less straight-line and one-dimensional transfer of knowledge and skills, are found in Derrida's concept of dérive.

Phase transitions driven by topological excitations and their tensor network approach

The fundamental concepts of phases of matter and thermal phase transitions constitute the cornerstone of our understanding of the physical universe. The historical development of the phase transition theory from Landau's spontaneous symmetry breaking paradigm to modern topological phase transition theories represents a major milestone in the evolution of numerous scientific disciplines. From the perspective of emergent philosophy, the interplay of topological excitations leads to enriched physical phenomena. One prominent prototype is the Berezinskii-Kosterlitz-Thouless (BKT) phase transition, where unbinding of integer vortices occurs in the absence of spontaneous breaking of continuous <i>U</i>(1) symmetry. Using the state-of-the-art tensor network methods, we express the partition function of the two-dimensional <i>XY</i>-related system in terms of a product of one-dimensional transfer operators. From the singularities of the entanglement entropy of the one-dimensional transfer operator, we accurately determine the complete phase diagram of the partition function. This method provides new insights into the emergent phenomenon driven by topological excitations, and sheds new light on future studies of 2D systems with continuous symmetries.

Hygro-thermal coupling in earth building materials

Raw earth is emerging as a viable building material with lower carbon emissions than conventional concrete and fired bricks. Raw earth is as an excellent passive hygro-thermal regulator, which improves occupants’ comfort while reducing the need for active heating/cooling installations. The coupled hygro-thermal response of earth materials is investigated by exploiting the principles of the thermodynamics of porous media and unsaturated soil mechanics. The degree of coupling between temperature and relative humidity (or water content) depends on the adopted simplifying assumptions. Some of these assumptions are valid for traditional building materials but may not be applicable to raw earth characterised by relatively high levels of liquid/gas permeability. The validity of current approaches is here assessed with reference to earth building via a simple one-dimensional transfer model, which simulates the behaviour of an unbounded earth wall subjected to time-dependent boundary conditions on the two faces. For typical values of water and vapour permeability, the complexity of the governing equations can be greatly reduced by neglecting variations of vapour mass and the dependency of suction on temperature without significantly reducing accuracy. Results are also strongly influenced by both initial state and water retention properties of the earth material.

Rarefied Broad-line Regions in Active Galactic Nuclei: Anomalous Responses in Reverberation Mapping and Implications for Weak Emission-line Quasars

Reverberation mapping (RM) is a widely used method for probing the physics of broad-line regions (BLRs) in active galactic nuclei (AGNs). There is increasing preliminary evidence that the RM behaviors of broad emission lines are influenced by BLR densities; however, the influences have not been investigated systematically from a theoretical perspective. In this paper, we adopt a locally optimally emitting cloud model and use CLOUDY to obtain the one-dimensional transfer functions of the prominent UV and optical emission lines for different BLR densities. We find that the influences of BLR densities to RM behaviors mainly have three aspects. First, rarefied BLRs (with low gas densities) may show anomalous responses in RM observations. Their emission-line light curves inversely respond to the variations in continuum light curves, which may have been observed in some UV RM campaigns. Second, the different BLR densities in AGNs may result in correlations between the time lags and equivalent widths of emission lines, and may contribute to the scatters of the radius–luminosity relationships. Third, the variations in BLR densities may explain the changes in time lags in individual objects for different years. Some weak emission-line quasars are probably extreme cases of rarefied BLRs. We predict that their RM observations may show anomalous responses.

Terminal-dependent ion recognition of BiOBr/PPy hybrid film with befitting absorption function for rapidly selective bromine ions removal

The further development of promising electrically switched ion exchange (ESIX) materials with considerable selectivity and large adsorption capacity have been generally concerned in ion removal filed. Herein, a hybrid film with core–shell structure and large lattice spacing, which integrated the virtues of highly adsorptive-selective BiOBr with conductive PPy was explored to be able to synergistically remove bromine ions (Br−) from an aqueous solution by combining density functional theory (DFT) calculations with experiments. The large-area and intimate contact between BiOBr and PPy generate a built-in electric field with quasi one-dimensional charge transfer from BiOBr to PPy, inducing the activation of CC conjugated bonds with the facilitating of the structure stability and electroactivity. Interestingly, the cooperation of PPy could significantly facilitate Br− migration on account of enhancing electroactivity without affecting the adsorption capacity of BiOBr. Meanwhile, BiOBr/PPy exhibits prominent selective capacity towards Br− in the presence of other competing ions, attributing to the shielding effect of PPy, particular electron transfer between Br and Bi, sucking stability and rapid ion kinetic diffusion accelerated by befitting adsorption capacity. Furthermore, the reversible redox process demonstrates that Bi(3−x)+OBr1−x with a Bi-terminated dependent manner could store Br− in the formation of BiOBr through an ESIX procedure (Bi(3−x)+OBr1−x + xBr−↔Bi3+OBr + xe−). It is expected that this study might propel the development of electroactive materials in the ion treatment field.

Estimation of the Acoustic Properties of the Random Packing Structures of Granular Materials: Estimation of the Sound Absorption Coefficient Based on Micro-CT Scan Data

In this study, the sound absorption properties of randomly packed granular materials were estimated. Generally, it is difficult to construct a general mathematical model for the arrangement of randomly packed granular materials. Therefore, in this study, an attempt was made to estimate the sound absorption coefficient using a theoretical analysis by introducing data from computed tomography (CT) scans, as the tomographic images of CT scans correspond to the slicing and elemental division of packing structures. In the theoretical analysis, the propagation constants and characteristic impedances in the voids were obtained by approximating each tomographic image as a void between two parallel planes. The derived propagation constants and characteristic impedances were then treated as a one-dimensional transfer matrix in the propagation of sound waves, and the transfer matrix method was used to calculate the normal incident sound absorption coefficient. The theoretical value of the sound absorption coefficient was derived using the effective density to which the measured tortuosity was applied. As a result, for the theoretical values considering the tortuosity, in many cases, the theoretical values were close to the measured values. For the theoretical values, when both the surface area and tortuosity were considered, the peak sound absorption frequency moved to a lower frequency and was in general agreement with the measured values.