Journal articles: 'Model materiálu Voce'

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Du, Zhehua, and Xin Lin. "Mathematical Model of VOCs Emission in Three-layer Building Materials." E3S Web of Conferences 257 (2021): 03047. http://dx.doi.org/10.1051/e3sconf/202125703047.

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A simple mathematical model is proposed to account for emissions of Volatile Organic Compounds (VOCs) from three-layer building materials. The model considers both the diffusion within three layer building materials and the mass transfer resistance through the air boundary layer. A general solution method based on Laplace transform is presented. Compared to other models capable of accounting for emissions of VOCs from multi layer building materials, the present model is fully analytical instead of being numerical. The present model was validated by the experimental data from the specially designed test. The results indicated that there was a good agreement between the model predictions and the experimental data. It can also be seen from calculation that model ignoring the boundary layer resistance cannot fully reflect the real situation.

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Liu, Xiaoyu, Zhishi Guo, Leslie E. Sparks, and Nancy F. Roache. "VOC Sink Behaviour on Building Materials – Model Evaluation." Indoor and Built Environment 20, no. 6 (July 8, 2011): 661–76. http://dx.doi.org/10.1177/1420326x11409461.

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The event of 11 September 2001 underscored the need to study the vulnerability of buildings to weapons of mass destruction, including chemical, biological, physical and radiological agents. Should these agents be released inside a building, they would interact with interior surfaces, building materials and furnishings, and could remain for a long period in an indoor environment. This study provides insights into the sink effect and absorption mechanisms of volatile organic compounds (VOCs) in indoor environments. In this study, the sink effect was investigated with building materials (e.g. painted gypsum wallboard, vinyl flooring, carpet and mortar) and VOCs, ethylbenzene, 1-butanol, decane and dodecane, which were used as surrogates of toxic chemicals. Vinyl flooring has the strongest sink for ethylbenzene and dodecane. The sink experimental data were employed to evaluate the Langmuir-isotherm and diffusion sink models. Test data were also compared to a no-sink model. The sorption and desorption rate constants for the Langmuir-isotherm model were obtained. Mass balance was analysed. There were strong correlations between equilibrium partition coefficients from the Langmuir-isotherm model and equilibrium partition coefficients and the effective diffusion coefficients from the sink diffusion model.

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Son, Hyoung-Seo, Young-Gon Kim, Jin-Jae Kim, and Young-Suk Kim. "Development of a Novel Plastic Hardening Model Based on Random Tree Growth Method." Korean Journal of Metals and Materials 58, no. 11 (November 5, 2020): 741–51. http://dx.doi.org/10.3365/kjmm.2020.58.11.741.

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The flow functions for plastic deformation have been developed to describe the plastic behavior of sheet metals. In order to explain the plastic behavior of material in metal forming processes via finite element analyses, two basic input functions should be applied. One is the yield function that determines the yielding behavior. The other is flow function to describe the hardening property of sheet metal. To describe the hardening properties of sheet materials under quasi-static tension condition in a wide range of plastic straining, various different equations are known such as classical Swift, Voce, Holloman, combined Swift-Voce, and recently proposed Kim-Tuan equations, etc. Those hardening equations are based on metallurgical or phenomenological investigations, and however the application of each equation has some limitation. In this study, the random growth of the binary tree method is introduced to develop the reliable hardening equations of various sheet metals (i.e. DP980, Pure Ti, AA5052-O, STS304, Ti-Gr2, and Mg-AZ31B) with no knowledge of existing hardening equation types. To evaluate the proposed method, the proposed equations developed by new approach are compared with the Voce, Swift, and Kim-Tuan hardening equations for stress-strain curve and the plastic instability point. Consequently, the proposed approach was proven to be very efficient to find the reliable and accurate hardening equation for any kind of materials.

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Reinić, Iva, and Elvis Žic. "Fizikalni model procjeđivanja vode kroz porozni materijal." Zbornik radova 21, no. 1 (March 11, 2019): 209–24. http://dx.doi.org/10.32762/zr.21.1.13.

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U ovom radu opisana su osnovna načela i vladajuće jednadžbe za opis strujanja podzemne vode kroz porozni materijal. U svrhu dobivanja mjerodavnih vrijednosti pojedinih karakterističnih fizikalnih veličina kod strujanja podzemne vode u pjeskovitom poroznom materijalu (brzina procjeđivanja, ekvipotencijal u određenoj točki unutar prostora, hidraulički gradijenti, protok i sl.) korišten je fizikalni model GUNT HM169 koji čini sastavni dio hidrotehničkog laboratorija Građevinskog fakulteta Sveučilišta u Rijeci. U radu je opisan princip rada za navedeni fizikalni model te način pripreme samih eksperimentalnih pokusa. U tom pogledu, izrađeno je nekoliko hidrodinamičkih analiza strujanja podzemne vode u odnosu na varijabilnost potencijala gornje i donje vode, analiza strujanja ispod vertikalnog čeličnog žmurja (dijafragme) te analiza opstrujavanja podzemne vode ispod prostorno trapezno izmodelirane prirodne nasute brane. Za potrebe provođenja pokusa, nasuta brana ručno je izrađena od pleksi stakla. Svrha istraživanja kroz fizikalni model HM169 bila je dobivanje jasnije slike strujnog polja ispod pojedinih hidrotehničkih objekata i, posljedično, dobivanje simulacijskih prikaza propagacije toka podzemne vode koja je praćena žutim fluorescin traserom.

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Deng, Baoqing, and Chang Nyung Kim. "An analytical model for VOCs emission from dry building materials." Atmospheric Environment 38, no. 8 (March 2004): 1173–80. http://dx.doi.org/10.1016/j.atmosenv.2003.11.009.

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Cao, Lian Ying, and Jun Shen. "An Analytical Model for Vocs Emission from Porous Building Materials." Advanced Materials Research 113-116 (June 2010): 1861–64. http://dx.doi.org/10.4028/www.scientific.net/amr.113-116.1861.

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This paper presented a new analytical model of partial differential equations (pde) for volatile organic compounds (vocs) emission from porous building materials. By applying Laplace transformation the representations for vocs concentration in the chamber and in the porous building material were given. The emission curves and average concentrations of some porous building materials Medium Density Fiberboards (mdf) in an airtight chamber were obtained. Result of the present model shows a good agreement with the experimental data.

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Kosztyła-Hojna, Bożena, Maciej Zdrojkowski, and Emilia Duchnowska. "The recommended presbyphonia recognition model in elderly men." Otolaryngologia Polska 73, no. 4 (August 8, 2019): 1–5. http://dx.doi.org/10.5604/01.3001.0013.3335.

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Introduction. The process of aging begins after 60 years of age and is referred to as presbyphonia (Vox senium). The causes include functional or organic voice disorders, often coexisting with dry upper respiratory tract infection. Materials and methods. The aim of the study is the use of High-Speed camera and acoustic voice analysis in diagnostics of the clinical form of presbyphonia. The study included group of 50 men, non-smokers, age from 51 to 72, who do not use voice professionally. High-Speed Digital Imaging and HS camera have been used, allowing evaluation of real vibrations of vocal folds, along with acoustic voice analysis using software by DiagNova Technologies. Results. VHI questionnaire has been used for self-assessment of voice disability. Visualization of the larynx enabled recognition of hypofunctional dysphonia or atrophy of vocal folds that cause voice disorders. This was confirmed by parameters of voice acoustic evaluation: F0, NHR, narrowband spectrography. Pathological value of NHR and the presence of nonharmonic components in the range of high frequency levels indicated glottal insufficiency, recorded with the visualization technique of the larynx by HS camera. A significant shortening of maximum phonation time in relation to the control group has also been recorded. Discussion. The objective examination of voice pathology is crucial in the diagnosis and rehabilitation, however, the subjective assessment of patient is important in the scope of the procedure used. Subjective self-assessment of patients voice (VHI) confirmed the sense of voice disorders in elderly men, indicating the need for rapid and accurate clinical diagnosis.

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KIM, JONG-BONG, and HYUNHO SHIN. "PREDICTION OF A MODIFIED PTW MODEL FOR VARIOUS TAYLOR IMPACT TESTS OF TANTALUM." International Journal of Modern Physics B 22, no. 31n32 (December 30, 2008): 6247–52. http://dx.doi.org/10.1142/s0217979208051868.

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The strain hardening part of the Preston-Tonks-Wallace (PTW) model, developed for the description of the plastic constitutive behavior of materials at wide ranges of strain, strain rate, and temperature, has been modified by employing the Voce equation. The prediction capability of the modified PTW (MPTW) has been investigated with reference to Taylor impact test results in the literature, and comparison has been made with the models of Johnson-Cook (JC), Steiberg-Guinan (SG), Zerilli-Armstrong (ZA), and PTW. Of the compared existing models, no model was appropriate for describing the results of various Taylor impact tests. However, the modified PTW is shown to predict fairly accurate results in terms of the length, diameter, and shape of the deformed specimen tested at different temperatures and impact velocity.

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Wang, C. N., J. R. Chang, and W. C. Chang. "Influences of Diaphragm Materials on the Performance of a Microspeaker." Journal of Mechanics 31, no. 3 (April 10, 2015): 331–36. http://dx.doi.org/10.1017/jmech.2015.4.

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ABSTRACTThe purpose of this study was to investigate the influence of a diaphragm material on the performance of a microspeaker. The finite element method was adopted to analyze the mode shapes and the displacement of the diaphragm under a force load. The Rayleigh integral was then calculated to determine the radiated sound pressure and frequency response of a loudspeaker. The location of the voice coil was also investigated. Locating the voice coil at approximately 53% to 76% of coil-radius/diaphragm-radius ratio yielded a favorable mode shape distribution and performance for the loudspeaker. In addition, two loudspeaker designs, Models A and B, were analyzed to determine the effects of the diaphragm material. The numerical results of Models A and B, indicated that the mode shape is a crucial factor when considering the materials used in a loudspeaker diaphragm. The property of a material at the inflection point of a mode shape obviously affects the modal frequency. According to this observation, the most crucial first and second axial symmetric modes in a loudspeaker design can be adjusted and the performance can be improved.

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D’Amico, Alessandro, Agnese Pini, Simone Zazzini, Daniela D’Alessandro, Giovanni Leuzzi, and Edoardo Currà. "Modelling VOC Emissions from Building Materials for Healthy Building Design." Sustainability 13, no. 1 (December 27, 2020): 184. http://dx.doi.org/10.3390/su13010184.

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The profound qualitative changes of indoor air and the progressive increase in the absolute number of pollutants, combined with the scientific awareness of the health impacts deriving from spending more than 90% of one’s time inside confined spaces, have increased the attention onto the needs of well-being, hygiene, and the health of users. This scientific attention has produced studies and analyses useful for evidence-based insights into building performance. Among the main pollutants in the indoor environment, Volatile Organic Compounds (VOCs) play a central role, and the use of box-models using the mass balance approach and Computational Fluid Dynamics (CFD) models are now consolidated to study their concentrations in an indoor environment. This paper presents the use of both types of modelling for the prediction of the VOC concentration in the indoor environment and the proposal of a guide value for the Indoor Air Quality (IAQ)-oriented building design, specifically related to the indoor VOC concentration due to building materials. Methodologically, the topic is addressed through environmental sampling, the definition of the parameters necessary for the numerical models, the simulations with the box-model and the CFD, and the comparison between the results. They show a good correspondence between the modelling tools used, highlighting the central role of ventilation and allowing a discussion of the relationship between regulatory limits of emissivity of materials and Indoor Air Guide Values for the concentration of pollutants.

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Koo, Gyeong-Hoi, and Ji-Hyun Yoon. "Inelastic Material Models of Type 316H for Elevated Temperature Design of Advanced High Temperature Reactors." Energies 13, no. 17 (September 2, 2020): 4548. http://dx.doi.org/10.3390/en13174548.

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In this paper, the inelastic material models for Type 316H stainless steel, which is one of the principal candidate materials for elevated temperature design of the advanced high temperature reactors (HTRs) pressure retained components, are investigated and the required material parameters are identified to be used for both elasto-plastic models and unified viscoplastic models. In the constitutive equations of the inelastic material models, the kinematic hardening behavior is expressed with the Chaboche model with three backstresses, and the isotropic hardening behavior is expressed by the Voce model. The required number of material parameters is minimized to be ten in total. For the unified viscoplastic model, which can express both the time-independent plastic behavior and the time-dependent viscous behavior, the constitutive equations have the same kinematic and isotropic hardening parameters of the elasto-plastic material model with two additional viscous parameters. To identify the material parameters required for these constitutive equations, various uniaxial tests were carried out at isothermal conditions at room temperature and an elevated temperature range of 425–650 °C. The identified inelastic material parameters were validated through the comparison between tests and calculations.

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Yang, X., Q. Chen, J. S. Zhang, Y. An, J. Zeng, and C. Y. Shaw. "A mass transfer model for simulating VOC sorption on building materials." Atmospheric Environment 35, no. 7 (January 2001): 1291–99. http://dx.doi.org/10.1016/s1352-2310(00)00397-6.

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Weigl, M., C. Fürhapper, S. Niedermayer, E. Habla, M. Nohava, S. Nagl, and S. Polleres. "VOC emissions from building materials: results from lab and model room trials." International Wood Products Journal 5, no. 3 (August 2014): 136–38. http://dx.doi.org/10.1179/2042645314y.0000000072.

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Djouabi, Mustapha, Abdelaziz Ati, and Pierre-Yves Manach. "Identification strategy influence of elastoplastic behavior law parameters on Gurson–Tvergaard–Needleman damage parameters: Application to DP980 steel." International Journal of Damage Mechanics 28, no. 3 (April 26, 2018): 427–54. http://dx.doi.org/10.1177/1056789518772130.

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This work adopts elastic–plastic/damage coupling in order to describe tensile behavior with validation on the deep-drawing test of a DP980 Dual Phase steel sheet. The damage model used is the Gurson–Tvergaard–Needleman (GTN model). The hardening laws used are those of Swift (non-saturating law), Voce (saturating law), Hockett-Sherby (saturating law) and the two combined laws Swift/Hockett-Sherby and Swift/Voce. An identifying method for elastic–plastic parameters and GTN damage model parameters is presented using the software modeFRONTIER. This method based on the inverse analysis is also proposed for the identification of weighting coefficient α of the Swift/Hockett-Sherby combined hardening law. Finally, a parametric study was carried out to show that the plastic modulus can be considered as another criterion for the choice of a hardening law. Dependence of the damage model parameters to the hardening law is clearly established. The different behavior laws are introduced via a VUHARD type subroutine in the calculation code Abaqus.

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Won, Doyun, Daniel M. Sander, C. Y. Shaw, and Richard L. Corsi. "Validation of the surface sink model for sorptive interactions between VOCs and indoor materials." Atmospheric Environment 35, no. 26 (September 2001): 4479–88. http://dx.doi.org/10.1016/s1352-2310(01)00223-0.

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Piasecki, Michał, Krystyna Barbara Kostyrko, and Anna Goljan. "The Ability to Control VOC Emissions from Multilayer Building Materials." Applied Sciences 11, no. 11 (May 24, 2021): 4806. http://dx.doi.org/10.3390/app11114806.

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The work aimed to investigate which parameters of the electrically powered radiant floor heating system are connected with the intensity of VOC total emissions and emissions from individual layers, which can be effectively changed and controlled to obtain energy savings in the ventilation process. For this purpose, experimental studies of VOC emissions from specially designed LRFHS samples (Laboratory Radiant Floor Heating System) were carried out, along with simulations of real thermal conditions of samples of layered systems containing separate heaters and various materials layers. The TD-GC-MS chromatography was used to assess the trends of VOCs concentration changes in 480 h in a test chamber (simulating real conditions) for several LRFHS systems of multilayer construction products with built-in individual heating systems, in two stabilised temperatures, 23 °C and 33 °C, two stabilised relative humidities, 50% and 80% and three air exchanges per hour ACH on levels 0.5, 1.0 and 1.5. The obtained results indicate that the models used to determine emissions from single-layer products correspond to the description of emissions from multilayer systems only to a limited extent; some inner layers of floor systems are giving diffusion resistance or intensification of diffusion. A new emission model is proposed. The time-emission concentration curves for dry and wet environments differ significantly; reducing the VOC concentration in the air for the number of exchanges above 1.0 ACH is relatively inefficient. Authors also mapped out new research directions; for example, the experiment showed that not all of the VOC contaminants are ventilated just as easily and perhaps, considering their concentration of resistant impurities, chemical structure and diffusion resistance through the layers, there is a need to determine their weights.

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Xu, Ying, and Yinping Zhang. "An improved mass transfer based model for analyzing VOC emissions from building materials." Atmospheric Environment 37, no. 18 (June 2003): 2497–505. http://dx.doi.org/10.1016/s1352-2310(03)00160-2.

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Deng, Baoqing, Ru Li, and Chang Nyung Kim. "A multi-phase model for VOC emission from single-layer dry building materials." Korean Journal of Chemical Engineering 26, no. 4 (July 2009): 919–24. http://dx.doi.org/10.1007/s11814-009-0154-2.

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Frezzini, Maria Agostina, Lorenzo Massimi, Maria Luisa Astolfi, Silvia Canepari, and Antonella Giuliano. "Food Waste Materials as Low-Cost Adsorbents for the Removal of Volatile Organic Compounds from Wastewater." Materials 12, no. 24 (December 17, 2019): 4242. http://dx.doi.org/10.3390/ma12244242.

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The aim of this work was to study the potential of food waste materials (banana peel, potato peel, apple peel, lemon peel, coffee waste, decaf coffee waste, grape waste, and carob peel) as low-cost adsorbents for the removal of aliphatic and aromatic volatile organic compounds (VOCs) from wastewater. The ability of examined food waste materials to adsorb VOCs from synthetic multi-component standard solutions was evaluated and the examined food waste materials showed high removal efficiency. Performances of coffee waste, grape waste, and lemon peel were detailed by using Trichloroethylene and p-Xylene in mono-component standard solutions. The adsorption capacity of the three selected food wastes was determined by using linear Langmuir and Freundlich isotherm models. Two errors functions, average percentage error (APE) and the chi-square test (χ2), were used for isotherm optimization prediction. Freundlich isotherm well described the adsorption of VOCs on the considered materials. According to the obtained results, a multilayer, physical, and cooperative adsorption process was hypothesized, particularly evident when the VOCs’ concentrations are high. This was confirmed by the high adsorption efficiency percentages (E% > 80%) of VOCs from a real polluted matrix (urban solid waste leachate), containing high concentrations of total organic content.

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Zhu, Lei, Baoqing Deng, and Yuan Guo. "A unified model for VOCs emission/sorption from/on building materials with and without ventilation." International Journal of Heat and Mass Transfer 67 (December 2013): 734–40. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2013.08.092.

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Turkmen, H. S., M. P. Miller, P. R. Dawson, and J. C. Moosbrugger. "A Slip-Based Model for Strength Evolution During Cyclic Loading." Journal of Engineering Materials and Technology 126, no. 4 (October 1, 2004): 329–38. http://dx.doi.org/10.1115/1.1789967.

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Motivated by the strong dependence of strain-hardening processes on slip system activity, a slip system hardening formulation that explicitly employs accumulated slip system shear strains and net crystal shearing rates is introduced within a polycrystal plasticity modeling formulation for predicting material response during cyclic deformation. The model, which is a slight modification of the Voce hardening model commonly employed for large strain forming simulations, was employed to model the behavior of 304L stainless steel subjected to uniaxial and multiaxial nonproportional multiple-step experiments and multiaxial multiple-phase angle experiments. The model successfully captured the pseudosaturation response that is common during the multiple-step tests and captured many of the loop-shape and stress-level features of the multiple-phase angle experiments.

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Lavrishchev, Anton, Andrey Litvinovich, Olga Pavlova, and Vladimir Bure. "Effect of liming of sod-podzolic soils with by-products of steel production on soil acidity and composition of wash water (column experiments)." Zemljiste i biljka 69, no. 2 (2020): 68–81. http://dx.doi.org/10.5937/zembilj2002068l.

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The waste slag materials from metallurgical plants contain calcareous materials, such as blast furnace (BFS) and converter slags (CS) of the Chelyabinsk Metallurgical Plant. However, the widespread use of these materials is limited by the presence of harmful impurities in their composition that can have a negative effect on soils and plants. The aim of our research is to study the effect of liming of soddypodzolic soils with metallurgical slags on the pHKCl value and the composition of the wash water. In a model experiment on columns, the migration ability of alkali metals from soils of light granulometric composition was studied after using two phases of steelmaking waste as a lime material. Research results indicate that the ameliorative properties of BFS and converter slags were different. When liming with BFS slag, a month after composting, the pHKCl value increased to 5.1 units. Studied soil from the category of "strongly acidic" moved to the category of "weakly acidic". When liming with the converter slag, the pHKCl value of the soil increased from 4.1 to 4.7 (the soil from the "strongly acidic" category moved to the "medium acidic" category). With an increase in the period of washing, the pH of the infiltration water increases. In the treatments with the use of BFS slag this increase was higher due to the continuing dissolution of ameliorants and the higher chemical activity of BFS slag. The liming led to intensive migration of alkaline earth metals. In the treatments limed with more soluble (chemically active) BFS slag, calcium losses were higher. Empirical estimation of alkaline earth metals leaching from the soil allowed to model the dynamics of the base migration. The dynamics of Ca and Mg migration from the soil were fundamentally different (content of Ca decreased, and of Mg increased). The dynamics of Ca migration from the soil limed with converter slag was most pronounced in comparison with the Ca dynamics for BFS slag and the Mg dynamics in all treatments.

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de Castro e Sousa, Albano, Yusuke Suzuki, and Dimitrios Lignos. "Consistency in Solving the Inverse Problem of the Voce-Chaboche Constitutive Model for Plastic Straining." Journal of Engineering Mechanics 146, no. 9 (September 2020): 04020097. http://dx.doi.org/10.1061/(asce)em.1943-7889.0001839.

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KONDO, Yasushi, Shuzo MURAKAMI, Shinsuke KATO, Jun-ichi FUJIMURA, Kazuhide ITO, and Akira YAMAMOTO. "MODELING OF MASS DIFFUSION IN POROUS SOLIDS AND PREDICTION OF INDOOR VOCs CONCENTRATION BASED ON MACROSCOPIC MODEL : Physical model and numerical analysis of VOCs emission from building materials Part 1." Journal of Architecture and Planning (Transactions of AIJ) 65, no. 535 (2000): 15–21. http://dx.doi.org/10.3130/aija.65.15_3.

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FUJIMURA, Jun-ichi, Shuzo MURAKAMI, Shinsuke KATO, Yasushi KONDO, and Yuto TADOKORO. "MODELING OF MASS DIFFUSION IN POROUS SOLIDS AND PREDICTION OF INDOOR VOCs CONCENTRATION BASED ON MACROSCOPIC MODEL : Physical model and numerical analysis of VOCs emission from building materials Part 2." Journal of Architecture and Planning (Transactions of AIJ) 66, no. 542 (2001): 57–61. http://dx.doi.org/10.3130/aija.66.57_2.

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Cho, Jae Hyung, Hyung Wuk Kim, and Suk Bong Kang. "Overview of Modeling Strength Evolution during Friction Stir Welding." Materials Science Forum 575-578 (April 2008): 805–10. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.805.

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Using two-dimensional Eulerian formulations coupling viscoplastic flow and heat transfer, the behaviors of aluminum alloys and stainless steel during FSW were overviewed. The plastic behaviors of the materials are complicated and the flow stresses are depending on deformation rate, temperature and deformation histories. Constitutive equations considering both strain hardening from accumulation of crystal defects and softening from recovery or recrystallization were used to model the materials. Strain hardening is incorporated with a strength that evolves with deformation rate and temperature along streamlines in the flow field. Strength evolutions have a Voce-like saturation limit because of the severe plastic deformation during FSW process. The model equations for kinematic and temperature were solved using the standard finite element method. The evolution equation for the strength is integrated along streamlines. The strength and temperature distribution vary with process conditions and constitutive equations. Stainless steel and AA6061 have different strengthening mechanisms. Modified constitutive equations were applied to reflect microstructural features of each material.

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Rusinek, Rafal, Marcin Szymanski, and Robert Zablotni. "Biomechanics of the Human Middle Ear with Viscoelasticity of the Maxwell and the Kelvin–Voigt Type and Relaxation Effect." Materials 13, no. 17 (August 27, 2020): 3779. http://dx.doi.org/10.3390/ma13173779.

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The middle ear is one of the smallest biomechanical systems in the human body and is responsible for the hearing process. Hearing is modelled in different ways and by various methods. In this paper, three-degree-of-freedom models of the human middle ear with different viscoelastic properties are proposed. Model 1 uses the Maxwell type viscoelasticity, Model 2 is based on the Kelvin–Voigt viscoelasticity, and Model 3 uses the Kelvin–Voigt viscoelasticity with relaxation effect. The primary aim of the study is to compare the models and their dynamic responses to a voice excitation. The novelty of this study lies in using different models of viscoelasticity and relaxation effect that has been previously unstudied. First, mathematical models of the middle ear were built, then they were solved numerically by the Runge–Kutta procedure and finally, numerical results were compared with those obtained from experiments carried out on the temporal bone with the Laser Doppler Vibrometer. The models exhibit differences in the natural frequency and amplitudes near the second resonance. All analysed models can be used for modelling the rapidly changing processes that occur in the ear and to control active middle ear implants.

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Boulinguiez, B., and P. Le Cloirec. "Biogas pre-upgrading by adsorption of trace compounds onto granular activated carbons and an activated carbon fiber-cloth." Water Science and Technology 59, no. 5 (March 1, 2009): 935–44. http://dx.doi.org/10.2166/wst.2009.070.

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The study assesses the adsorption onto activated carbon materials of selected volatile organic compounds -VOCs- (dichloromethane, 2-propanol, toluene, siloxane D4) in a biogas matrix composed of methane and carbon dioxide (55:45 v/v). Three different adsorbents are tested, two of them are granular activated carbon (GAC), and the last is an activated carbon fiber-cloth (ACFC). The adsorption isotherm data are fitted by different models by nonlinear regression. The Langmuir-Freundlich model appears to be the adequate one to describe the adsorption phenomena independently of the VOC considered or the adsorbent. The adsorbents present attractive adsorption capacity of the undesirable compounds in biogas atmosphere though the maximum adsorption capacities for a VOC are quite different from each other. The adsorption kinetics are characterized through three coefficients: the initial adsorption coefficient, the external film mass transfer coefficient and the internal diffusion coefficient of Weber. The ACFC demonstrates advanced kinetic yields compared to the granular activated carbon materials whatever VOC is considered. Therefore, pre-upgrading of biogas produced from wastewater sludge or co-digestion system by adsorption onto activated carbon appears worth investigating. Especially with ACFC material that presents correct adsorption capacities toward VOCs and concrete regeneration process opportunity to realize such process.

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Liu, Yanfeng, Xiaojun Zhou, Dengjia Wang, Cong Song, and Jiaping Liu. "A diffusivity model for predicting VOC diffusion in porous building materials based on fractal theory." Journal of Hazardous Materials 299 (December 2015): 685–95. http://dx.doi.org/10.1016/j.jhazmat.2015.08.002.

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Frazão, José, Susana I. C. J. Palma, Henrique M. A. Costa, Cláudia Alves, Ana C. A. Roque, and Margarida Silveira. "Optical Gas Sensing with Liquid Crystal Droplets and Convolutional Neural Networks." Sensors 21, no. 8 (April 18, 2021): 2854. http://dx.doi.org/10.3390/s21082854.

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Liquid crystal (LC)-based materials are promising platforms to develop rapid, miniaturised and low-cost gas sensor devices. In hybrid gel films containing LC droplets, characteristic optical texture variations are observed due to orientational transitions of LC molecules in the presence of distinct volatile organic compounds (VOC). Here, we investigate the use of deep convolutional neural networks (CNN) as pattern recognition systems to analyse optical textures dynamics in LC droplets exposed to a set of different VOCs. LC droplets responses to VOCs were video recorded under polarised optical microscopy (POM). CNNs were then used to extract features from the responses and, in separate tasks, to recognise and quantify the vapours exposed to the films. The impact of droplet diameter on the results was also analysed. With our classification models, we show that a single individual droplet can recognise 11 VOCs with small structural and functional differences (F1-score above 93%). The optical texture variation pattern of a droplet also reflects VOC concentration changes, as suggested by applying a regression model to acetone at 0.9–4.0% (v/v) (mean absolute errors below 0.25% (v/v)). The CNN-based methodology is thus a promising approach for VOC sensing using responses from individual LC-droplets.

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Seitz, M., M. Schwager, and A. Burdack-Freitag. "Simulation von VOC-Emissionssequenzen unter Zuhilfenahme des Hybridmodells/Simulation of VOC emission sequences by means of the hybrid model." Gefahrstoffe 80, no. 04 (2020): 151–57. http://dx.doi.org/10.37544/0949-8036-2020-04-45.

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Emissionsuntersuchungen unterschiedlichster Materialien auf mensch- und umweltgefährliche flüchtige organische Verbindungen (volatile organic compounds, VOC) weisen auf ein zeitabhängiges Emissionsverhalten hin. In der vorliegenden Arbeit wurde anhand eines Vorhersagemodells ein prinzipieller Trend von Emissionskonzentrationen berechnet und mit empirisch ermittelten Daten unterlegt. Zunächst wurde auf Basis von vorliegenden Daten eine Clusterung von VOC vorgenommen und infrage kommende Faktoren aufgegriffen, die einen Einfluss auf das Emissionsverhalten von VOC haben können. Danach wurde eine Priorisierung der Einflussfaktoren auf der Grundlage experimen- teller Beobachtungen und publizierter Daten vorgenommen. Anhand eines stark emittierenden polymeren Materials wurden beispielhaft, unter Verwendung einer Emissionsprüfkammer, Emissionskonzentrationsmessungen durchgeführt. Im Anschluss wurden über ein mathematisches Modell die grafischen Verläufe simuliert. Die realen Daten belegten das Rechenmodell, seine prinzipielle Anwendbarkeit und die vorgenommene Clusterung.

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Hodgetts, William, Qi Song, Xinyue Xiang, and Jacqueline Cummine. "On a Vector towards a Novel Hearing Aid Feature: What Can We Learn from Modern Family, Voice Classification and Deep Learning Algorithms." Applied Sciences 11, no. 12 (June 18, 2021): 5659. http://dx.doi.org/10.3390/app11125659.

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(1) Background: The application of machine learning techniques in the speech recognition literature has become a large field of study. Here, we aim to (1) expand the available evidence for the use of machine learning techniques for voice classification and (2) discuss the implications of such approaches towards the development of novel hearing aid features (i.e., voice familiarity detection). To do this, we built and tested a Convolutional Neural Network (CNN) Model for the identification and classification of a series of voices, namely the 10 cast members of the popular television show “Modern Family”. (2) Methods: Representative voice samples were selected from Season 1 of Modern Family (N = 300; 30 samples for each of the classes of the classification in this model, namely Phil, Claire, Hailey, Alex, Luke, Gloria, Jay, Manny, Mitch, Cameron). The audio samples were then cleaned and normalized. Feature extraction was then implemented and used as the input to train a basic CNN model and an advanced CNN model. (3) Results: Accuracy of voice classification for the basic model was 89%. Accuracy of the voice classification for the advanced model was 99%.; (4) Conclusions: Greater familiarity with a voice is known to be beneficial for speech recognition. If a hearing aid can eventually be programmed to recognize voices that are familiar or not, perhaps it can also apply familiar voice features to improve hearing performance. Here we discuss how such machine learning, when applied to voice recognition, is a potential technological solution in the coming years.

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Hsieh, Chien-Te, and Jin-Ming Chen. "Adsorption Energy Distribution Model for VOCs onto Activated Carbons." Journal of Colloid and Interface Science 255, no. 2 (November 2002): 248–53. http://dx.doi.org/10.1006/jcis.2002.8668.

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Song, Zijie, Zhiqiang Hu, and Jonas W. Ringsberg. "Critical Void Volume Fraction Identification Based on Mesoscopic Damage Model for NVA Shipbuilding Steel." Journal of Marine Science and Application 18, no. 4 (October 15, 2019): 444–56. http://dx.doi.org/10.1007/s11804-019-00117-2.

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Abstract NVA mild steel is a commonly used material in the shipbuilding industry. An accurate model for description of this material’s ductile fracture behaviour in numerical simulation is still a challenging task. In this paper, a new method for predicting the critical void volume fraction fc in the Guson-Tvergaard-Needleman (GTN) model is introduced to describe the ductile fracture behaviour of NVA shipbuilding mild steel during ship collision and grounding scenarios. Most of the previous methods for determination of the parameter fc use a converse method, which determines the values of the parameters through comparisons between experimental results and numerical simulation results but with high uncertainty. A new method is proposed based on the Hill, Bressan, and Williams hypothesis, which reduces the uncertainty to a satisfying extent. To accurately describe the stress-strain relationship of materials before and after necking, a combination of the Voce and Swift models is used to describe the material properties of NVA mild steel. A user-defined material subroutine has been developed to enable the application of the new parameter determination method and its implementation in the finite element software LS-DYNA. It is observed that the model can accurately describe structural damage by comparing the numerical simulation results with those of experiments; thus, the results demonstrate the model’s capacity for structural response prediction in ship collision and grounding scenario simulations

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Liu, Yanfeng, Xiaojun Zhou, Dengjia Wang, Cong Song, and Jiaping Liu. "A prediction model of VOC partition coefficient in porous building materials based on adsorption potential theory." Building and Environment 93 (November 2015): 221–33. http://dx.doi.org/10.1016/j.buildenv.2015.06.025.

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Xu, Ying, and Yinping Zhang. "A general model for analyzing single surface VOC emission characteristics from building materials and its application." Atmospheric Environment 38, no. 1 (January 2004): 113–19. http://dx.doi.org/10.1016/j.atmosenv.2003.09.020.

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De Jonge, Klaas, Arnold Janssens, and Jelle Laverge. "Performance assessment of demand controlled ventilation controls concerning indoor VOC exposure based on a dynamic VOC emission model." E3S Web of Conferences 111 (2019): 01051. http://dx.doi.org/10.1051/e3sconf/201911101051.

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The performance assessment of ventilation systems often focusses only on CO2 and humidity levels. The indoor Volatile Organic Compounds (VOC) emissions of building materials or other products is thereby overlooked. The new generation of ventilation systems, Demand Controlled Ventilation (DCV), are systems that do not supply the nominal airflow continuously but are controlled by CO2 or humidity sensors in order to save energy. This poses potential problems for exposure to VOCs. In this study, a dynamic VOC model, which takes into account changing temperature and humidity that was derived from literature, is implemented in a CONTAM model of the Belgian reference apartment. The impact of a DCV system on the indoor VOC levels is investigated. Results show that the use of a dynamic model is necessary compared to the previously used approximation of a constant emission. Furthermore, on a system level, the influence of the ventilation system control on the indoor VOC levels shows. The overall VOC concentration in the different rooms will be higher because of lowered ventilation rates. Especially in rooms that are often unoccupied during the day, the accumulation of VOCs shows. In the development of DCV system controls, the aspect of VOC exposure should not be overlooked to be able to benefit from both the energy savings and improved Indoor Air Quality (IAQ).

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Yurttadur, Gizem, Faruk Ayhan Bascıftcı, and Kayhan Ozturk. "The effects of rapid maxillary expansion on voice function." Angle Orthodontist 87, no. 1 (July 27, 2016): 49–55. http://dx.doi.org/10.2319/010416-008.1.

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ABSTRACT Objective: To evaluate the effects of rapid maxillary expansion (RME) on vocal function in patients with bilateral maxillary crossbite. Materials and Methods: We designed our research as a prospective, controlled, clinical study. The treatment group and the control group each had 20 subjects for a total of 40 subjects. Acoustic voice samples were recorded from all patients at T1 and T2 by the Multi-Dimensional Voice Program (MDVP Model 5105) for acoustic analysis in Computerized Speech Lab (CSL). Results: No statistically significant differences were found between the treatment and control groups in the means of any parameters. Conclusions: RME does not change vocal quality or resonance, so it can be safely used with patients.

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Capilla, Gustavo, Hiroshi Hamasaki, Fusahito Yoshida, Toshiya Suzuki, and Kazuo Okamura. "Determination of the Anisotropic Hardening of Sheet Metals at Large Strain from Stretch Bending Test." Key Engineering Materials 725 (December 2016): 677–82. http://dx.doi.org/10.4028/www.scientific.net/kem.725.677.

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The present study aims to determine stress-strain curves at large strains of sheet metals under the uniaxial stress state by using the in-plane stretch-bending test. The combined Swift-Voce model, which describes the large-strain work-hardening of materials by means of a weighting coefficient μ, was used for FE simulation of the stretch-bending. The coefficient μ was determined by minimizing the difference in punch stroke vs. bending strain responses between the experimental data and the corresponding experimental results. By using this inverse approach, stress-strain curves of two levels of high-strength steel sheets of a precipitation hardening type, 590R and 780R, in three sheet directions (0, 45 and 90o from rolling direction), were determined.

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Lasota, Martin, Petr Šidlof, Manfred Kaltenbacher, and Stefan Schoder. "Impact of the Sub-Grid Scale Turbulence Model in Aeroacoustic Simulation of Human Voice." Applied Sciences 11, no. 4 (February 23, 2021): 1970. http://dx.doi.org/10.3390/app11041970.

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In an aeroacoustic simulation of human voice production, the effect of the sub-grid scale (SGS) model on the acoustic spectrum was investigated. In the first step, incompressible airflow in a 3D model of larynx with vocal folds undergoing prescribed two-degree-of-freedom oscillation was simulated by laminar and Large-Eddy Simulations (LES), using the One-Equation and Wall-Adaptive Local-Eddy (WALE) SGS models. Second, the aeroacoustic sources and the sound propagation in a domain composed of the larynx and vocal tract were computed by the Perturbed Convective Wave Equation (PCWE) for vowels [u:] and [i:]. The results show that the SGS model has a significant impact not only on the flow field, but also on the spectrum of the sound sampled 1 cm downstream of the lips. With the WALE model, which is known to handle the near-wall and high-shear regions more precisely, the simulations predict significantly higher peak volumetric flow rates of air than those of the One-Equation model, only slightly lower than the laminar simulation. The usage of the WALE SGS model also results in higher sound pressure levels of the higher harmonic frequencies.

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Raillard, C., V. Héquet, P. Le Cloirec, and J. Legrand. "Photocatalytic oxidation of volatile organic compounds present in airborne environment adjacent to sewage treatment plants." Water Science and Technology 49, no. 1 (January 1, 2004): 111–14. http://dx.doi.org/10.2166/wst.2004.0032.

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Emissions of volatile organic compounds (VOCs) from wastewater in municipal sewage or industrial wastewater treatment plants are often overlooked as sources of exposure to hazardous substances. The impact of such emissions on local airborne environments represents a growing source of scientific, toxicological and public health interest. Actually, VOCs are suspected to be quite dangerous for human health. Some of them belong to the family of odorous compounds and can cause serious annoyance in the neighbourhood of the emission sources. A way to remove VOCs released from sewers and wastewater treatment facilities could be to degrade them by photocatalytic oxidation. TiO2-based photocatalysts are known to be efficient for this kind of application. In the present work TiO2 P25 Degussa was deposited on glass supports. These materials were tested for the degradation of butanone-2 in a photocatalytic reactor. The influence of water vapour (relative humidity) was shown using the Langmuir-Hinshelwood kinetic model.

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Ye, Wei, Hao Wang, Zean Chen, and Xu Zhang. "Ozone Deposition on Free-Running Indoor Materials and the Corresponding Volatile Organic Compound Emissions: Implications for Ventilation Requirements." Applied Sciences 10, no. 12 (June 16, 2020): 4146. http://dx.doi.org/10.3390/app10124146.

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Recently, tropospheric ozone has become a public health concern worldwide, along with the continuous battle against ambient fine particulate matter in countries like China. In this study, we investigate the impact of indoor ozone pollution using seven materials categorized as either wood-based panels or synthetic fibers, which were freely-stored in an office/lab environment. Most materials were considered as used and aged more than 1–2 years. An experimental apparatus was used to study ozone deposition and detect volatile organic compound (VOC) emissions from the specimens when exposed to ozone at three concentration levels: <10, 100, and 300 ppb. A simplified model is proposed to discuss ventilation requirements based on a standard room. We found that the mean ozone deposition velocities from the seven materials ranged from 0.005 to 0.062 cm·s−1. Both the engineering wood and some of the synthetic fibers were, moreover, prone to ozone deposition. Second, 15 VOCs were found in the sampling air from a 24-VOC target list after ozone exposure. The emission rates of the VOCs from all seven materials were then determined. Third, when the ozone concentration in the outdoor air is not severely high, it is possible to use ventilation to maintain acceptable indoor air quality.

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Lee, C. S., F. Haghighat, and W. S. Ghaly. "A study on VOC source and sink behavior in porous building materials - analytical model development and assessment." Indoor Air 15, no. 3 (June 2005): 183–96. http://dx.doi.org/10.1111/j.1600-0668.2005.00335.x.

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Vittoni, Chiara, Giorgio Gatti, Ilaria Braschi, Enrico Buscaroli, Giovanni Golemme, Leonardo Marchese, and Chiara Bisio. "Toluene Adsorption by Mesoporous Silicas with Different Textural Properties: A Model Study for VOCs Retention and Water Remediation." Materials 13, no. 12 (June 12, 2020): 2690. http://dx.doi.org/10.3390/ma13122690.

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In this work, different mesoporous silicas were studied as potential sorbents for toluene, selected as a model molecule of aromatic organic fuel-based pollutants. Three siliceous materials with different textural and surface properties (i.e., fumed silica and mesoporous Santa Barbara Amorphous (SBA)-15 and Mobil Composition of matter (MCM)-41 materials) were considered and the effect of their physico-chemical properties on the toluene adsorption process was studied. In particular, FT-IR spectroscopy was used to qualitatively study the interactions between the toluene molecule and the surface of silicas, while volumetric adsorption analysis allowed the quantitative determination of the toluene adsorption capacity. The combined use of these techniques revealed that textural properties of the sorbents, primarily porosity, are the driving forces that control the adsorption process. Considering that, under real conditions of usage, the sorbents are soaked in water, their hydrothermal stability was also investigated and toluene adsorption by both the gas and aqueous phase on hydrothermally pre-treated samples was studied. The presence of ordered porosity, together with the different pore size distribution and the amount of silanol groups, strongly affected the adsorption process. In toluene adsorption from water, SBA-15 performed better than MCM-41.

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Kolesau, Aliaksei, and Dmitrij Šešok. "Voice Activation for Low-Resource Languages." Applied Sciences 11, no. 14 (July 7, 2021): 6298. http://dx.doi.org/10.3390/app11146298.

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Voice activation systems are used to find a pre-defined word or phrase in the audio stream. Industry solutions, such as “OK, Google” for Android devices, are trained with millions of samples. In this work, we propose and investigate several ways to train a voice activation system when the in-domain data set is small. We compare self-training exemplar pre-training, fine-tuning a model pre-trained on another domain, joint training on both an out-of-domain high-resource and a target low-resource data set, and unsupervised pre-training. In our experiments, the unsupervised pre-training and the joint-training with a high-resource data set from another domain significantly outperform a strong baseline of fine-tuning a model trained on another data set. We obtain 7–25% relative improvement depending on the model architecture. Additionally, we improve the best test accuracy on the Lithuanian data set from 90.77% to 93.85%.

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De Girolamo Del Mauro, Anna, Angelica Immacolata Grimaldi, Vera La Ferrara, Ettore Massera, Maria Lucia Miglietta, Tiziana Polichetti, and Girolamo Di Francia. "A Simple Optical Model for the Swelling Evaluation in Polymer Nanocomposites." Journal of Sensors 2009 (2009): 1–6. http://dx.doi.org/10.1155/2009/703206.

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In the present study, we report on a simple optical method based on thin film interferometry for the swelling evaluation in polymer nanocomposite layers used for gas sensing applications. We show that white light interferometry can be profitably applied to characterize scattering materials such as polymer/carbon black nanocomposites. A properly adjusted experimental setup was implemented to monitor the swelling behavior of the sensitive films in real device operating conditions. In particular, the behavior of poly(2-hydroxyethyl methacrylate) (PHEMA) and of carbon black/PHEMA nanocomposite layers, used for volatile organic compounds (VOCs) detection, was investigated and measured under ethanol vapors exposure (max 1%). The method is very sensitive and the swelling in the range of only few nanometers can be measured. Interestingly, we have found that the nanocomposite undergoes a more pronounced swelling process with respect to pristine polymer. Ethanol diffusion coefficients in the nanocomposite were evaluated.

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Borghesi, C., and J. P. Bouchaud. "Spatial correlations in vote statistics: a diffusive field model for decision-making." European Physical Journal B 75, no. 3 (May 19, 2010): 395–404. http://dx.doi.org/10.1140/epjb/e2010-00151-1.

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Oboe, Roberto, Federico Marcassa, and Giuseppe Maiocchi. "Voltage driven hard disk drive with voice coil model-based control." Microsystem Technologies 11, no. 7 (June 23, 2005): 478–87. http://dx.doi.org/10.1007/s00542-005-0592-7.

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Liu, Yutong, and Tao Tian. "Fabrication of Diatomite/Silicalite-1 Composites and Their Property for VOCs Adsorption." Materials 12, no. 4 (February 13, 2019): 551. http://dx.doi.org/10.3390/ma12040551.

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Adsorption technology is an effective method to remove volatile organic compounds (VOCs). In this work, we prepared hierarchical porous materials using modified diatomite (Dt) as a support and nano-sized silicalite-1 (S-1) seeds as inorganic fillers, which were applied to adsorb volatile organic compounds (VOCs). The characterization of the composites indicated that S-1 was successfully coated onto the surface of modified Dt, and the best surface area of the composites was 398.8 m2/g, nearly 40 times as large as Dt. The adsorption capacities of Dt/S-1 composites for three probe VOCs (ethyl acetate, acetone, and toluene) were rather superior to Dt, and the composites had preferential adsorption selectivity for ethyl acetate. Effects of seeded zeolite contents and hydrothermal conditions for the adsorption capacity of composites were discussed in this paper. The composite seeded with 5 wt% S-1 zeolite, which was subsequently synthesized by hydrothermal reaction at 100 °C for four days, showed the maximum adsorption capacity (1.31 mmol/g for ethyl acetate). The pseudo second-order model provided a perfect fit to adsorption kinetics, while the Langmuir model agreed the best with the adsorption isotherms. In addition, the composites had selective adsorption to ethyl acetate among these three probes VOCs. The regeneration experiments were also carried out, and the adsorption efficiency of the adsorbents was still up to 67% after five adsorption–desorption cycles. The hierarchical porous Dt/S-1 composites have an excellent VOC adsorption performance, satisfactory selectivity, and recycling ability.

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Schlegel, Patrick, Kirsten Wong, Mamdouh Aker, Yazeed Alhiyari, and Jennifer Long. "Objective Assessment of Porcine Voice Acoustics for Laryngeal Surgical Modeling." Applied Sciences 11, no. 10 (May 14, 2021): 4489. http://dx.doi.org/10.3390/app11104489.

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Pigs have become important animal models in voice research. Several objective parameters exist to characterize the pig voice, but it is not clear which of them are sensitive to the impaired voice quality after laryngeal injury or surgery. In order to conduct meaningful voice research in pigs, it is critical to have standard functional voice outcome measures that can distinguish between normal and impaired voices. For this reason, we investigated 17 acoustic parameters before and early after surgery in three Yucatan mini pigs. Four parameters showed consistent changes between pre- and post-surgery recordings, mostly related to decreased spectral energy in higher frequencies after surgery. We recommend two of these, 50% spectral energy quartile (Q50) and Flux, for objective functional voice assessment of pigs undergoing laryngeal surgery. The long-term goal of this process is to enable quantitative voice outcome tracking of laryngeal surgical interventions in porcine models.

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Journal articles on the topic 'Model materiálu Voce'

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