Articles de revues : « Absorption estimation »

1

HEANEY, ROBERT P. « Estimation of True Calcium Absorption ». Annals of Internal Medicine 103, n^o 4 (1 octobre 1985) : 516. http://dx.doi.org/10.7326/0003-4819-103-4-516.

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Heaney, R. P., R. R. Recker et K. Kasper. « Estimation of True Calcium Absorption ». Nutrition in Clinical Practice 1, n^o 1 (février 1986) : 59. http://dx.doi.org/10.1177/088453368600100120.

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Glicksohn, Joseph, Boaz Mourad et Eyal Pavell. « Imagination, Absorption and Subjective Time Estimation ». Imagination, Cognition and Personality 11, n^o 2 (octobre 1991) : 167–76. http://dx.doi.org/10.2190/1gn7-qvmb-bv80-qj1y.

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Luo, Jie, Yongming Zhang et Qixing Zhang. « Effects of black carbon morphology on brown carbon absorption estimation : from numerical aspects ». Geoscientific Model Development 14, n^o 4 (23 avril 2021) : 2113–26. http://dx.doi.org/10.5194/gmd-14-2113-2021.

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Abstract. In this work, we developed a numerical method to investigate the effects of black carbon (BC) morphology on the estimation of brown carbon (BrC) absorption using the absorption Ångström exponent (AAE) methods. Pseudo measurements of the total absorption were generated based on several morphologically mixed BC models, then the BrC absorption was inferred based on different BC AAE methods. By investigating the estimated BrC absorption at different parameters, we have demonstrated under what conditions the AAE methods can provide good or bad estimations. As recent studies have shown that both externally and internally mixed BC still exhibits a relatively small fractal dimension value, the AAE = 1 method is still a reasonable method to estimate the BrC absorption as the AAE of fluffy BC does not deviate significantly from 1. However, the deviation between the “true” and the estimated BrC mass absorption cross section (MAC) should also be carefully considered as sometimes the MAC deviation estimated using the AAE = 1 method can reach a value that is comparable to the true BrC MAC for internally mixed particles. The Mie AAE method can just provide relatively reasonable estimations for small particles, and the BrC absorption deviations estimated using the Mie AAE methods are rather substantial for large particles. If the BC core still exhibits a fluffy structure, the deviation between the true and the estimated BrC MAC can reach 4.8 and 5.8 m2/g for large externally and internally mixed particles, respectively. Even for a compact BC core, the BrC MAC deviation estimated using the Mie AAE method can reach approximately 2.8 m2/g when the BC size is large. By comparing the AAE of spherical BC and detailed BC models, we found that the AAE does not deviate significantly from 1 if BC presents a fluffy fractal structure, while it varies considerably with particle size if BC exhibits a spherical structure, and the AAE value of spherical BC can vary from a negative value to approximately 1.4. The precalculated wavelength dependence of AAE (WDA) method does not necessarily improve the estimations. In many cases, the WDA method even provides a worse estimation than the BC AAE =1 and Mie AAE methods. Our results showed that the WDA does not deviate significantly from 0 if the BC core presents a fluffy structure, while the WDA of spherical BC can vary significantly as the particle size changes. The deviation between the true and the estimated BrC MAC using the WDA method can reach approximately 9 m2/g for externally mixed particles, which is far more than BrC MAC itself. As recent studies have shown that BC commonly exhibits a fluffy structure but not a spherical structure, the estimation of BrC absorption based on the AAE method should carefully consider the effects of BC morphologies.

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Graves, David A., et Keith S. Rotenberg. « Pseudoephedrine absorption from controlled release formulations : Absorption rate constant estimation methods ». Biopharmaceutics & ; Drug Disposition 10, n^o 2 (mars 1989) : 127–36. http://dx.doi.org/10.1002/bdd.2510100203.

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Franceschini, Emilie, Marie-Christine Pauzin, Serge Mensah et Jean-Philippe Groby. « Soft tissue Absorption Tomography with Correction for Scattering Aberrations ». Ultrasonic Imaging 27, n^o 4 (octobre 2005) : 221–36. http://dx.doi.org/10.1177/016173460502700402.

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Among the many factors involved in ultrasound attenuation phenomena, scattering effects play a major role, even in the unexpected case of soft tissues. It is proposed in this study to quantitatively evaluate the scattering affecting the measurements before reconstructing the absorption parameter alone. The reconstruction procedure involves three steps: (1) Estimating the sound speed map using a transmission tomography algorithm. This estimation procedure provides a numerical phantom of the organ probed, cleared of all dissipative components. This absorption free phantom mimics the (viscoacoustic) tissues imaged except for the density and absorption characteristics: the density a priori equals 1000 kg/m3 and the absorption is not taken into account. The impedance fluctuations in the object are therefore approximated on the basis of the sound speed contrast. (2) Synthesing the field scattered by the absorption free phantom; the attenuation observed here results solely from the scattering phenomenon. The synthesis is carried out using a finite-element time domain code simulating the ultrasonic propagation through the phantom. It provides the scattering distortion reference introduced into the log spectral absorption estimator. (3) Reducing the scattering distortions affecting the integrated absorption measured along the ray paths using a log spectral procedure. The corrected integrated absorption is then processed using a tomographic reconstruction procedure that provides an estimate of the absorption distribution. Simple numerical simulations show the improvement obtained in the absorption estimates with this approach.

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Charles, Heimsath. « Small-Area Population Estimation in Absorption Analysis ». Journal of Real Estate Research 6, n^o 3 (1 janvier 1991) : 315–26. http://dx.doi.org/10.1080/10835547.1991.12090655.

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Heino, Jenni, et Erkki Somersalo. « Estimation of optical absorption in anisotropic background ». Inverse Problems 18, n^o 3 (8 avril 2002) : 559–73. http://dx.doi.org/10.1088/0266-5611/18/3/304.

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Heaney, Robert P., Mary Susan Dowell et Randi L. Wolf. « Estimation of True Calcium Absorption in Men ». Clinical Chemistry 48, n^o 5 (1 mai 2002) : 786–88. http://dx.doi.org/10.1093/clinchem/48.5.786.

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Mobasheri, Mohammad Reza, Meisam Amani, Mahin Beikpour et Sahel Mahdavi. « Soil moisture content estimation using water absorption bands ». Geomatica 73, n^o 3 (1 septembre 2019) : 63–73. http://dx.doi.org/10.1139/geomat-2018-0020.

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Soil moisture content (SMC) is a crucial component in various environmental studies. Although many models have been proposed for SMC estimation, developing new models for accurate estimation of SMC is still an interesting subject. This study aimed to develop new models for SMC estimation using the water absorption bands in the spectral signatures of three different soil types: loam, silty loam, and sandy loam. Based on the three absorption bands (i.e., 1400, 1900, and 2200 nm) and regression analyses, six approaches were considered. These scenarios were generally based on the reflectance value and its logarithm, as well as the difference between the wet and dry reflectance values for the absorption bands. Finally, 24 models were developed for SMC estimation from the three different soil types, as well as the entire soil samples. The most accurate SMC, as indicated by the lowest root mean squared error (RMSE) and the highest correlation coefficient (r), was obtained from the model developed using the logarithm of the average values reflectance in the three water absorption bands for sandy loam (RMSE = 0.31 g/kg, r = 0.99). Overall, using the spectrometry data derived in the lab, the results of the proposed models were promising and demonstrate great potential for SMC estimation using spectral data collected by satellites in the future studies.

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Hu, Dong, Yuping Huang, Qiang Zhang, Lijian Yao, Zidong Yang et Tong Sun. « Numerical Simulation on Spatial-Frequency Domain Imaging for Estimating Optical Absorption and Scattering Properties of Two-Layered Horticultural Products ». Applied Sciences 11, n^o 2 (10 janvier 2021) : 617. http://dx.doi.org/10.3390/app11020617.

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Spatial-frequency domain imaging (SFDI) is a wide-field, noncontact, and label-free imaging modality that is currently being explored as a new means for estimating optical absorption and scattering properties of two-layered turbid materials. The accuracy of SFDI for optical property estimation, however, depends on light transfer model and inverse algorithm. This study was therefore aimed at providing theoretical analyses of the diffusion model and inverse algorithm through numerical simulation, so as to evaluate the potential for estimating optical absorption and reduced scattering coefficients of two-layered horticultural products. The effect of varying optical properties on reflectance prediction was first simulated, which indicated that there is good separation in diffuse reflectance over a large range of spatial frequencies for different reduced scattering values in the top layer, whereas there is less separation in diffuse reflectance for different values of absorption in the top layer, and even less separation for optical properties in the bottom layer. To implement the nonlinear least-square method for extracting the optical properties of two-layered samples from Monte Carlo-generated reflectance, five curve fitting strategies with different constrained parameters were conducted and compared. The results confirmed that estimation accuracy improved as fewer variables were to be estimated each time. A stepwise method was thus suggested for estimating optical properties of two-layered samples. Four factors influencing optical property estimation of the top layer, which is the basis for accurately implementing the stepwise method, were investigated by generating absolute error contour maps. Finally, the relationship between light penetration depth and spatial frequency was studied. The results showed that penetration depth decreased with the increased spatial frequency and also optical properties, suggesting that appropriate selection of spatial frequencies for a stepwise method to estimate optical properties from two-layered samples provides potential for estimation accuracy improvement. This work lays a foundation for improving optical property estimation of two-layered horticultural products using SFDI.

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Hu, Dong, Yuping Huang, Qiang Zhang, Lijian Yao, Zidong Yang et Tong Sun. « Numerical Simulation on Spatial-Frequency Domain Imaging for Estimating Optical Absorption and Scattering Properties of Two-Layered Horticultural Products ». Applied Sciences 11, n^o 2 (10 janvier 2021) : 617. http://dx.doi.org/10.3390/app11020617.

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Spatial-frequency domain imaging (SFDI) is a wide-field, noncontact, and label-free imaging modality that is currently being explored as a new means for estimating optical absorption and scattering properties of two-layered turbid materials. The accuracy of SFDI for optical property estimation, however, depends on light transfer model and inverse algorithm. This study was therefore aimed at providing theoretical analyses of the diffusion model and inverse algorithm through numerical simulation, so as to evaluate the potential for estimating optical absorption and reduced scattering coefficients of two-layered horticultural products. The effect of varying optical properties on reflectance prediction was first simulated, which indicated that there is good separation in diffuse reflectance over a large range of spatial frequencies for different reduced scattering values in the top layer, whereas there is less separation in diffuse reflectance for different values of absorption in the top layer, and even less separation for optical properties in the bottom layer. To implement the nonlinear least-square method for extracting the optical properties of two-layered samples from Monte Carlo-generated reflectance, five curve fitting strategies with different constrained parameters were conducted and compared. The results confirmed that estimation accuracy improved as fewer variables were to be estimated each time. A stepwise method was thus suggested for estimating optical properties of two-layered samples. Four factors influencing optical property estimation of the top layer, which is the basis for accurately implementing the stepwise method, were investigated by generating absolute error contour maps. Finally, the relationship between light penetration depth and spatial frequency was studied. The results showed that penetration depth decreased with the increased spatial frequency and also optical properties, suggesting that appropriate selection of spatial frequencies for a stepwise method to estimate optical properties from two-layered samples provides potential for estimation accuracy improvement. This work lays a foundation for improving optical property estimation of two-layered horticultural products using SFDI.

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Harris, Peter, Nadia Smith, Valerie Livina, Tom Gardiner, Rod Robinson et Fabrizio Innocenti. « Estimation of background gas concentration from differential absorption lidar measurements ». Atmospheric Measurement Techniques 9, n^o 10 (4 octobre 2016) : 4879–90. http://dx.doi.org/10.5194/amt-9-4879-2016.

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Abstract. Approaches are considered to estimate the background concentration level of a target species in the atmosphere from an analysis of the measured data provided by the National Physical Laboratory's differential absorption lidar (DIAL) system. The estimation of the background concentration level is necessary for an accurate quantification of the concentration level of the target species within a plume, which is the quantity of interest. The focus of the paper is on methodologies for estimating the background concentration level and, in particular, contrasting the assumptions about the functional and statistical models that underpin those methodologies. An approach is described to characterise the noise in the recorded signals, which is necessary for a reliable estimate of the background concentration level. Results for measured data provided by a field measurement are presented, and ideas for future work are discussed.

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Faidah, Adel. « Estimation of the Dispersion and Absorption Parameters of ». Journal of King Abdulaziz University-Science 21, n^o 2 (2009) : 185–96. http://dx.doi.org/10.4197/sci.21-2.1.

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Drummond, B. K., M. E. J. Curzon et M. Strong. « Estimation of Fluoride Absorption from Swallowed Fluoride Toothpastes ». Caries Research 24, n^o 3 (1990) : 211–15. http://dx.doi.org/10.1159/000261267.

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Gregoratto, D., et M. R. Bailey. « Estimation of lung absorption parameters for oxides of238Pu ». Journal of Radiological Protection 38, n^o 2 (juin 2018) : 831–53. http://dx.doi.org/10.1088/1361-6498/aac19d.

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Tibaldi, Rosalie, Wil ten Berge et Daniel Drolet. « Dermal Absorption of Chemicals : Estimation by IH SkinPerm ». Journal of Occupational and Environmental Hygiene 11, n^o 1 (14 novembre 2013) : 19–31. http://dx.doi.org/10.1080/15459624.2013.831983.

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Dong, Ren G., John Z. Wu, Daniel E. Welcome et Thomas W. McDowell. « Estimation of Vibration Power Absorption Density in Human Fingers ». Journal of Biomechanical Engineering 127, n^o 5 (23 mars 2005) : 849–56. http://dx.doi.org/10.1115/1.1992526.

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The absorption of hand-transmitted vibration energy may be an etiological factor in vibration-induced disorders. The vibration power absorption density (VPAD) may be a better measure of energy than the total power absorption of the hand-arm system. The objectives of the present study are to develop a method to estimate the average absorption density in the fingers and to investigate its basic characteristics. Ten healthy male subjects were used in this study. The biodynamic response of the fingers in a power grip subjected to a broad-band random excitation was measured under three grip forces (15, 30, 50N) and three push forces (35, 45, 50N). The response was used to estimate the total finger energy absorption. The response, together with the finger volume, was also used to estimate the amount of tissue effectively involved in the absorption. Then, the average VPAD under constant-acceleration, constant-power density, constant-velocity vibration spectra, and 20 tool vibration spectra were calculated. The correlations between the VPAD and the unweighted and weighted accelerations (ISO 5349-1, 2001) were also examined. The VPAD depends on both the characteristics of the vibration spectrum and the biodynamic response of the finger-hand-arm system. The biodynamic response generally plays a more important role in determining the VPAD in the middle frequency range (31.5-400Hz) than those at the low and high ends. The applied force significantly affected the VPAD. The finger VPAD was highly correlated to the unweighted acceleration. The average VPAD can be determined using the proposed experimental method. It can serve as an alternative tool to quantify the severity of the vibration exposure for studying vibration-induced finger disorders.

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Bannaga, Alamedin. « Trade liberalization and technology absorption in a less developing country context ». International Journal of Development Issues 14, n^o 2 (6 juillet 2015) : 149–70. http://dx.doi.org/10.1108/ijdi-12-2014-0085.

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Purpose – The paper aims to investigate the relationship between trade liberalization and technology absorption in a less developing country context. The objective is to empirically test the relationship between these two variables. This analysis was conducted in Sub-Saharan African economies. Design/methodology/approach – A panel regression of 20 countries in Sub-Saharan Africa was estimated based on a model that takes into account both trade policy and non-policy factors affecting technology absorption. Findings – A positive and significant relationship was found between trade liberalization and technology absorption. This relationship is valid across a variety of model specifications, technology absorption proxies and estimation techniques. Moreover, non-policy factors such as geographical spillover play significant role in technology absorption. Originality/value – The paper examines the link between the trade liberalization and the technology absorption in Sub-Saharan Africa. The analysis is empirical in nature and builds on panel estimations. The novelty of the paper comes from the topic investigated and the focus on a region which has not attracted much attention in the literature.

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Christiani, Natalia, Yayat Hidayat et Sutrisno Trisno. « CO2 Emission and Absorption Estimation in Bandung City by Implementing CO2 Emission Rate Reduction Simulation Using the Stella Program ». 3BIO : Journal of Biological Science, Technology and Management 3, n^o 1 (13 juillet 2021) : 28–41. http://dx.doi.org/10.5614/3bio.2021.3.1.4.

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Bandung CO2 emissions continue to increase in line with its population. The emissions source comes from the industrial, transportation, Liquefied Petroleum Gas (LPG), household, and livestock sectors, whereas CO2 absorption only comes from vegetation through photosynthesis. High CO2 emissions could decrease air quality and reduce environmental health. This study aims to estimate the amount of CO2 emissions and their absorption in Bandung by implementing CO2 Emission Rate Reduction Simulation (CERRS). The simulation comprises four scenarios, namely substitution of vehicle fuel and the application of smart driving techniques, optimization of waste processing in IWPS, processing 90% of livestock waste into biogas, and green space development of 30% of Bandung City area. Estimated CO2 emission and absorption rates were calculated for the next 10 years (2021-2030) using the Stella program version 9.0.2. The results showed that without implementing the CERRS, the amount of CO2 emissions in Bandung in 2030 was estimated to reach 10,983,666.82 tons while implementing the CERRS was 2,361,721.30 tons. Without implementing the CERRS, the estimated amount of CO2 absorptions in 2030 was 214,235.11 tons, while implementing the CERRS was 2,785,703.11 tons. It is expected that the application of the CERRS could reduce the level of CO2 emissions in Bandung by 78.5% and increase CO2 absorptions by 1,200.3%.

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Yahya, Iskandar, Arulampalam Kunaraj, Seri Mastura Mustaza, Steven Clowes et S. Ravi P. Silva. « Methods for Estimating Composition of Single Walled Carbon Nanotubes Based on Electronic Type ». Materials Science Forum 1055 (4 mars 2022) : 77–86. http://dx.doi.org/10.4028/p-073fwj.

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— Synthesized single-walled carbon nanotubes (SWCNTs) consist of a mixture of chiralities and therefore a post-synthesis separation is essential to separate them based on electronic type i.e., metallic (m-SWCNT) or semiconducting (s-SWCNT) for device applications. A key parameter to measure the effectiveness of separation process is the enrichment composition percentage between m-SWCNT and s-SWCNT, which can be estimated via several methods based on optical characterizations. In this paper, we compare the composition percentage estimations from 3 different methods based on Raman spectroscopy and UV-Vis optical absorption spectroscopy. The estimation methods are radial breathing mode (RBM) peak analysis, optical absorption area under curve (OUA) and first derivative amplitude of the optical absorption curve (FDA). Four different SWCNT sources were used in this study, which were subjected to post-synthesis separation process via agarose gel chromatography. Raman and UV-Vis spectroscopy measurements were carried out on all samples, before and after separation. From the estimations, we observed firstly that there are some variations on the estimated enrichment compositions between different methods, although the values are comparable. Secondly, for some SWCNTs samples, only a certain estimation method showed reliable composition percentage. The results presented in this work may provide viable options for characterizations of SWCNTs as there is no direct method to quantify the absolute composition percentage of SWCNTs based on electronic type. Keywords—single-walledcarbon nanotube, separation, electronic type, optical characterization, purity percentage.

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Dilungana, Stéphane, Antoine Deleforge, Cédric Foy et Sylvain Faisan. « Learning-based estimation of individual absorption profiles from a single room impulse response with known positions of source, sensor and surfaces ». INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, n^o 1 (1 août 2021) : 5623–30. http://dx.doi.org/10.3397/in-2021-3186.

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In situ estimation of the individual absorption profiles of a room remains a challenging problem in building acoustics. This work is aimed at studying the feasibility of this estimation in a shoebox room of fixed and known geometry, using a room impulse response measured from a source and sensor at fixed and known positions. This problem is tackled using supervised learning. Three neural network architectures are compared. Simulated training and validation sets featuring various types of perturbations (surface diffusion, geometrical errors and additive white Gaussian noise) are generated. An extensive empirical simulated study is carried out to determine the influence of these perturbations on the performances of learned models, and to determine which components of the room impulse response are most useful for absorption coefficients prediction. Trained models are shown to yield errors significantly smaller than those of a naive mean estimator on every simulated datasets, including those featuring realistic perturbation levels. Our study outlines the benefit of using convolutional neural network layers, especially when geometrical errors exist. It also reveals that early acoustic echoes are the most salient feature of room impulse responses for absorption coefficient prediction under a fixed geometry.

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Kotla, Suman Krishna, Ashish Saxena et Ramesh Saxena. « A Model To Estimate Glucose Absorption in Peritoneal Dialysis : A Pilot Study ». Kidney360 1, n^o 12 (29 septembre 2020) : 1373–79. http://dx.doi.org/10.34067/kid.0004722020.

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BackgroundGlucose absorption in patients on peritoneal dialysis (PD) may contribute to adverse metabolic effects. Previous studies on glucose absorption were done on patients on continuous ambulatory PD, with a long dwell time. However, the growing majority of contemporary patients on PD perform automated PD with a short dwell time. Moreover, membrane characteristics and dwell time determine small-solute transport across the peritoneal membrane.MethodsIn our pilot study, we used data from the peritoneal equilibration test (PET) to develop a model to estimate glucose absorption. In six randomly selected patients on PD, we calculated actual glucose absorption from directly measuring effluent glucose concentration. We then used the R programming language to create a nonlinear, least-squared regression model, inputting PET data, D2/D0, and D4/D0 to generate an exponential decay curve. This model was then used to estimate the fraction of glucose remaining in the dialysate at a particular dwell time t (Dt/D0). Daily glucose absorption was calculated by multiplying 1−Dt/D0 with the amount of glucose the patient was exposed to in 24 hours.ResultsWe observed the mean glucose absorption (89.7±28.8 g/d), as measured from the effluent, very close to our estimate (88.12±28.9 g/d), and the difference between the glucose estimation and actual absorption was not statistically significant (P>0.05), with "W" value of 8. After validating our hypothesis, we randomly selected an independent cohort of 11 patients with ESKD who were on various PD modalities and analyzed their data. We observed that the mean daily glucose absorption of 62.7±24.5 g (27.98–110.35 g), much lower than that reported in the literature, depends on dwell times and membrane characteristics in addition to the amount of glucose absorption in the cohort.ConclusionsOur model provides a simple tool for estimating glucose absorption and caloric load in contemporary patients on PD. Hopefully, the accurate estimation of caloric load and the incorporation of it into the daily caloric intake of the individual will help to reduce metabolic consequences of hyperglycemia and weight gain and improve overall outcomes of PD.

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Song, Xiaolei, Ji Yi et Jing Bai. « A Parallel Reconstruction Scheme in Fluorescence Tomography Based on Contrast of Independent Inversed Absorption Properties ». International Journal of Biomedical Imaging 2006 (2006) : 1–7. http://dx.doi.org/10.1155/ijbi/2006/70839.

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Based on an independent forward model in fluorescent tomography, a parallel reconstructed scheme for inhomogeneous mediums with unknown absorption property is proposed in this paper. The method considers the two diffusion equations as separately describing the propagation of excited light in tissues with and without fluorescent probes inside. Then the concentration of fluorophores is obtained directly through the difference between two estimations of absorption coefficient which can be parallel inversed. In this way, the multiparameter estimation problem in fluorescent tomography is transformed into two independent single-coefficient determined schemes of diffusion optical tomography (DOT). Any algorithms proved to be efficient and effective in DOT can be directly applied here. In this study the absorption property is estimated from the independent diffusion equations by a gradient-based optimization method with finite element method (FEM) solving the forward model. Simulation results of three representative occasions show that the reconstructed method can well estimate fluorescent property and tissue absorption distribution.

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Li, Hong, Wunian Yang, Junjie Lei, Jinxing She et Xiangshan Zhou. « Estimation of leaf water content from hyperspectral data of different plant species by using three new spectral absorption indices ». PLOS ONE 16, n^o 3 (30 mars 2021) : e0249351. http://dx.doi.org/10.1371/journal.pone.0249351.

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The leaf equivalent water thickness (EWT, g cm−2) and fuel moisture content (FMC, %) are key variables in ecological and environmental monitoring. Although a variety of hyperspectral vegetation indices have been developed to estimate the leaf EWT and FMC, most of these indices are defined considered two or three specific bands for a specific plant species, which limits their applicability. In this study, we proposed three new spectral absorption indices (SAI970, SAI1200, and SAI1660) for various plant types by considering the symmetry of the spectral absorption at 970 nm, 1200 nm and 1660 nm and spectral heterogeneity of different leaves. The indices were calculated considering the absorption peak and shoulder bands of each leaf instead of the same specific bands for all leaves. A pooled dataset of three tree species (camphor (VX), capricorn (VJ), and red-leaf plum (VL)) was used to test the performance of the SAIs in terms of the leaf EWT and FMC estimation. The results indicated that, first, SAI1200 was more suitable for estimating the EWT than FMC, whereas SAI970 and SAI1660 were more suitable for estimating the FMC. Second, SAI1200 achieved the most accurate estimation of the EWT with a cross-validation coefficient of determination (Rcv2) of 0.845 and relative cross-validation root mean square error (rRMSEcv) of 8.90%. Third, SAI1660 outperformed the other indices in estimating the FMC at the leaf level, with an Rcv2 of 0.637 and rRMSEcv of 8.56%. Fourth, SAI970 achieved a moderate accuracy in estimating the EWT (Rcv2 of 0.25 and rRMSEcv of 19.68%) and FMC (Rcv2 of 0.275 and rRMSEcv of 12.10%) at the leaf level. These results can enrich the application of the SAIs and demonstrate the potential of using SAI1200 to determine the leaf EWT and SAI1660 to obtain the leaf FMC among various plant types.

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Shah, ManishRamesh, RukeshR Patel, RandhirsinhV Solanki et ShailendraH Gupta. « Estimation of drug absorption in antibiotic soaked bone grafts ». Indian Journal of Orthopaedics 50, n^o 6 (2016) : 669. http://dx.doi.org/10.4103/0019-5413.193486.

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Kutsak, S. V., et L. M. Logacheva. « PARAMETER ESTIMATION OF THE H-PLANE ABSORPTION HARMONIC FILTER ». Telecommunications and Radio Engineering 74, n^o 9 (2015) : 797–806. http://dx.doi.org/10.1615/telecomradeng.v74.i9.50.

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Yang, Xiao-hua, Jing-feng Huang, Fu-min Wang, Xiu-zhen Wang, Qiu-xiang Yi et Yuan Wang. « A modified chlorophyll absorption continuum index for chlorophyll estimation ». Journal of Zhejiang University-SCIENCE A 7, n^o 12 (décembre 2006) : 2002–6. http://dx.doi.org/10.1631/jzus.2006.a2002.

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Stewart, Robert A., et Nicholas P. Chotiros. « Estimation of sediment volume scattering strength and absorption coefficient ». Journal of the Acoustical Society of America 86, S1 (novembre 1989) : S33. http://dx.doi.org/10.1121/1.2027462.

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Sarria, B., J. R. Dainty, T. E. Fox et S. J. Fairweather-Tait. « Estimation of iron absorption in humans using compartmental modelling ». European Journal of Clinical Nutrition 59, n^o 1 (14 juillet 2004) : 142–44. http://dx.doi.org/10.1038/sj.ejcn.1602030.

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Thongsinthusak, Thomas, John H. Ross, Steven G. Saiz et Robert I. Krieger. « Estimation of Dermal Absorption Using the Exponential Saturation Model ». Regulatory Toxicology and Pharmacology 29, n^o 1 (février 1999) : 37–43. http://dx.doi.org/10.1006/rtph.1998.1274.

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Turner, D. S. « Absorption coefficient estimation using a two-dimensional interpolation procedure ». Journal of Quantitative Spectroscopy and Radiative Transfer 53, n^o 6 (juin 1995) : 633–37. http://dx.doi.org/10.1016/0022-4073(95)00024-f.

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Ghosh, Nishith, Pallavee V.K., J. D. Sharma et A. S. Vajarekar. « Estimation of dermal absorption parameters of cleaning chemical ingredients ». Journal of Chemical Health and Safety 26, n^o 1 (janvier 2019) : 9–14. http://dx.doi.org/10.1016/j.jchas.2018.08.004.

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AIZU, Yoshihisa, et Tomonori YUASA. « Absorption of Light and Its Estimation in Skin Tissue ». Review of Laser Engineering 48, n^o 12 (2020) : 649. http://dx.doi.org/10.2184/lsj.48.12_649.

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Danilov, Valery A., et Il Moon. « A Method for Estimating Mass Transfer Coefficients in a Packed Column Using Reactive Absorption Data ». Collection of Czechoslovak Chemical Communications 70, n^o 3 (2005) : 383–402. http://dx.doi.org/10.1135/cccc20050383.

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This paper is devoted to the development of a new method for estimating mass transfer coefficients and effective area in packed columns in the case of reactive absorption. The method is based on a plug-flow model of reactive absorption of carbon dioxide with sodium hydroxide solution. The parameter estimation problem is solved using an optimization technique. Some mass transfer parameters are found to be correlated. Global sensitivity analysis by Sobol's technique showed that the unit model with the defined objective function is sensitive to the estimated parameter. Case studies of reactive absorption with different packings illustrate application of the proposed method for estimating mass transfer coefficients and effective area from column operation data. The model calculations are compared with experimental data obtained by other authors. The concentration profiles calculated by the unit model with the estimated parameters are shown to match well with experimental profiles from literature. A good agreement between estimated values and experimental data from literature confirms the applicability of this method.

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Adnan, Muhammad, Rachmi Meutia, Marwiyati Marwiyati et T. Hafizdhly Dinillah. « Modeling the MSME Sector on Labor Absorption in Aceh ». Jurnal Manajemen 14, n^o 1 (5 mars 2023) : 271. http://dx.doi.org/10.32832/jm-uika.v14i1.13485.

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<p><em>The existence of MSMEs in Aceh reduces unemployment by employing the working-age population. In addition, turnover for MSMEs is essential because an increase in turnover will impact the expansion of business units in the sector and increase the need for labor. This study aimed to test and analyze the effect of the number of business units and turnover on employment in the MSME sector in Aceh. This research used an associative quantitative approach. The panel data was used in this study including 23 districts/cities from 2018-2020 period. Panel data regression uses three estimation methods: the Common Effect model, the Fixed Effect model, and the Random Effect model. The Chow, Hausman, and Lagrange Multiplier tests are used to select the best estimation model. The Random Effect Model is the best estimation model in this study. Based on the estimation results, the number of business units and turnover positively and significantly affect employment in the MSME sector in Aceh. The variable number of business units has the most influence on work in the MSME sector in Aceh. The research conducted in Aceh province uses panel data in 23 districts/cities for the period 2018-2020 so that the results of this study can illustrate the existence of MSMEs in absorbing labor in Aceh Province.</em></p>

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Momber, A. W., et R. Kovacevic. « Quantification of Energy Absorption Capability in Abrasive Water Jet Machining ». Proceedings of the Institution of Mechanical Engineers, Part B : Journal of Engineering Manufacture 209, n^o 6 (décembre 1995) : 491–98. http://dx.doi.org/10.1243/pime_proc_1995_209_113_02.

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The paper contains a mathematical model for the estimation of the energy absorption capability of materials during abrasive water jet machining based on an energy balance inside the workpiece. A parameter χ(h) is defined to describe and calculate the energy absorption capability. A method for the estimation of this parameter is developed based on a parabolic striation model. It is shown that the energy absorption depends on the depth of cut following a second-order equation. The relation between the relative depth of cut h/hmax and the energy absorption capability χ(h) can also be described by a second-order equation. For such materials as aluminium, cast iron and stainless steel a critical point of abrasive water jet energy absorption is detected at a depth of cut of h = 0.52hmax, which corresponds to a striation angle of about 75°.

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Strocchi, Alessandra, et Michael D. Levitt. « Measurement of starch absorption in humans ». Canadian Journal of Physiology and Pharmacology 69, n^o 1 (1 janvier 1991) : 108–10. http://dx.doi.org/10.1139/y91-015.

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Although starch provides a large fraction of human caloric intake, there is limited information concerning the efficiency of intestinal absorption of this nutrient. Owing to the fermentation of starch by colonic bacteria, there is no quantitative test for starch absorption comparable to the fecal fat determination. The most accurate estimation of starch absorption has been obtained by intubating the terminal ileum and aspirating ileal contents following ingestion of a meal containing starch plus a nonabsorbable marker. Starch absorption is calculated from the ratio of starch:marker in the ileal aspirate relative to the ratio in the meal. Disadvantages of the technique are the requirement for ileal intubation and the possible adverse effect of intubation on the absorptive process. A more widely used technique to assess starch absorption involves measurement of breath hydrogen (H2) excretion after ingestion of starch. Malabsorbed starch is fermented by colonic bacteria with liberation of H2 that is absorbed and excreted in expired air. This test is simple and noninvasive and can provide quantitative measurements of starch malabsorption. Application of this technique has demonstrated that 5–10% of starch in wheat, potatoes, and corn is not absorbed by healthy subjects, while rice starch is nearly completely absorbed.Key words: starch, absorption, hydrogen, breath test, malabsorption.

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Batko, Wojciech, Paweł Pawlik et Grazyna Wszołek. « Sensitivity Analysis of the Estimation of the Single-Number Sound Absorption Evaluation Index DLα ». Archives of Acoustics 42, n^o 4 (20 décembre 2017) : 689–96. http://dx.doi.org/10.1515/aoa-2017-0071.

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Abstract Acoustic barriers are assigned to the respective categories of sound absorbing properties on the basis of a single-number sound absorption evaluation index. Categories of absorbing properties play a significant role in selecting the barrier type for the given localisation. The estimation of the single-number sound absorption evaluation index is performed, among others, by means of measuring the sound absorption coefficient of the analysed acoustic barrier sample in the reverberation chamber. The sensitivity analysis of the determination of the single-number sound absorption evaluation index was performed in this work. The estimation of the input parameters uncertainty contribution to the expanded uncertainty of the sound absorption evaluation index, was done first. The Monte Carlo method and the reduction interval arithmetic were used for this aim. The relative sensitivity coefficients were determined by means of the author’s method based on the interval arithmetic. These coefficients contain information concerning the quantitative influence of the given input value on the final result.

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Sakamoto, Shuichi, Kyosuke Suzuki, Kentaro Toda et Shotaro Seino. « 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 ». Materials 16, n^o 1 (29 décembre 2022) : 337. http://dx.doi.org/10.3390/ma16010337.

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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.

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Beeler, Payton, et Rajan K. Chakrabarty. « Constraining the particle-scale diversity of black carbon light absorption using a unified framework ». Atmospheric Chemistry and Physics 22, n^o 22 (22 novembre 2022) : 14825–36. http://dx.doi.org/10.5194/acp-22-14825-2022.

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Abstract. Atmospheric black carbon (BC), the strongest absorber of visible solar radiation in the atmosphere, manifests across a wide spectrum of morphologies and compositional heterogeneity. Phenomenologically, the distribution of BC among diverse particles of varied composition gives rise to enhancement of its light absorption capabilities by over twofold in comparison to that of nascent or unmixed homogeneous BC. This situation has challenged the modeling community to consider the full complexity and diversity of BC on a per-particle basis for accurate estimation of its light absorption. The conventionally adopted core–shell approximation, although computationally inexpensive, is inadequate not only in estimating but also capturing absorption trends for ambient BC. Here we develop a unified framework that encompasses the complex diversity in BC morphology and composition using a single metric, the phase shift parameter (ρBC), which quantifies how much phase shift the incoming light waves encounter across a particle compared to that in its absence. We systematically investigate variations in ρBC across the multi-space distribution of BC morphology, mixing state, mass, and composition as reported by field and laboratory observations. We find that ρBC>1 leads to decreased absorption by BC, which explains the weaker absorption enhancements observed in certain regional BC compared to laboratory results of similar mixing state. We formulate universal scaling laws centered on ρBC and provide physics-based insights regarding core–shell approximation overestimating BC light absorption. We conclude by packaging our framework in an open-source Python application to facilitate community-level use in future BC-related research. The package has two main functionalities. The first functionality is for forward problems, wherein experimentally measured BC mixing state and assumed BC morphology are input, and the aerosol absorption properties are output. The second functionality is for inverse problems, wherein experimentally measured BC mixing state and absorption are input, and the morphology of BC is returned. Further, if absorption is measured at multiple wavelengths, the package facilitates the estimation of the imaginary refractive index of coating materials by combining the forward and inverse procedures. Our framework thus provides a computationally inexpensive source for calculation of absorption by BC and can be used to constrain light absorption throughout the atmospheric lifetime of BC.

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Xiong, Yiong, et Yue Ming Yue. « New Spectral Indices as Indicators of Carotenoids Content ». Applied Mechanics and Materials 220-223 (novembre 2012) : 2983–86. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.2983.

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Carotenoids play a key role in adaptation of plants to light stress and other unfavorable ecological conditions. Remote sensing of carotenoids content still not well developed due to the absorptions overlap of chlorophyll a and carotenoids in the visible spectral range. In this study, for accurate estimation of carotenoids contents, an assumption of absorption in [450, 550nm] is proposed. That is, the spectral reflectance features in this range are comprehensive effects of chlorophyll (chl) and carotenoids (car) absorption. And the effects of chlorophyll and carotenoids were multiplicative in [450, 550nm] and a new spectral index was defined. The results showed that the new spectral index was strongly related to carotenoids and could be applied as the indicator of carotenoids content.

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Picard, Ghislain, Quentin Libois et Laurent Arnaud. « Refinement of the ice absorption spectrum in the visible using radiance profile measurements in Antarctic snow ». Cryosphere 10, n^o 6 (14 novembre 2016) : 2655–72. http://dx.doi.org/10.5194/tc-10-2655-2016.

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Abstract. Ice is a highly transparent material in the visible. According to the most widely used database (IA2008; Warren and Brandt, 2008), the ice absorption coefficient reaches values lower than 10−3 m−1 around 400 nm. These values were obtained from a vertical profile of spectral radiance measured in a single snow layer at Dome C in Antarctica. We reproduced this experiment using an optical fiber inserted in the snow to record 56 profiles from which 70 homogeneous layers were identified. Applying the same estimation method on every layer yields 70 ice absorption spectra. They present a significant variability but absorption coefficients are overall larger than IA2008 by 1 order of magnitude at 400–450 nm. We devised another estimation method based on Bayesian inference that treats all the profiles simultaneously. It reduces the statistical variability and confirms the higher absorption, around 2 × 10−2 m−1 near the minimum at 440 nm. We explore potential instrumental artifacts by developing a 3-D radiative transfer model able to explicitly account for the presence of the fiber in the snow. The simulation shows that the radiance profile is indeed perturbed by the fiber intrusion, but the error on the ice absorption estimate is not larger than a factor of 2. This is insufficient to explain the difference between our new estimate and IA2008. The same conclusion applies regarding the plausible contamination by black carbon or dust, concentrations reported in the literature are insufficient. Considering the large number of profiles acquired for this study and other estimates from the Antarctic Muon and Neutrino Detector Array (AMANDA), we nevertheless estimate that ice absorption values around 10−2 m−1 at the minimum are more likely than under 10−3 m−1. A new estimate in the range 400–600 nm is provided for future modeling of snow, cloud, and sea-ice optical properties. Most importantly, we recommend that modeling studies take into account the large uncertainty of the ice absorption coefficient in the visible and that future estimations of the ice absorption coefficient should also thoroughly account for the impact of the measurement method.

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Paramonov, Leonid E. « Estimation of chlorophyll content by absorption spectra of native Spirulina platensis cells ». Issues of modern algology (Вопросы современной альгологии), n^o 1(22) (2020) : 25–33. http://dx.doi.org/10.33624/2311-0147-2020-1(22)-25-33.

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A method for retrieving the absorption coefficients of Spirulina platensis pigments using absorption spectra of native cells and excluding the use of extracts is considered. Estimates of the intracellular concentration of chlorophyll a, С-phycoerythrin, С- phycocyanin and allophycocyanin in native cells are discussed.

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Gustafsson, Mats, Marius Cismasu et Sven Nordebo. « Absorption Efficiency and Physical Bounds on Antennas ». International Journal of Antennas and Propagation 2010 (2010) : 1–7. http://dx.doi.org/10.1155/2010/946746.

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The all spectrum absorption efficiency appears in the physical bounds on antennas expressed in the polarizability dyadics. Here, it is shown that this generalized absorption efficiency is close to 1/2 for small idealized dipole antennas and for antennas with a dominant resonance in their absorption. Also, the usefulness of this parameter is analyzed for estimation of antenna performance. The results are illustrated with numerical data for several antennas.

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Bannister, T. T. « Estimation of absorption coefficients of scattering suspensions using opal glass ». Limnology and Oceanography 33, n^o 4 (juillet 1988) : 607–15. http://dx.doi.org/10.4319/lo.1988.33.4.0607.

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Todo, Hiroaki. « Estimation of skin absorption of chemicals with Fick’s diffusion model ». Folia Pharmacologica Japonica 157, n^o 5 (2022) : 335–39. http://dx.doi.org/10.1254/fpj.22034.

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Todo, Hiroaki. « Estimation of Skin Absorption of Chemicals to Evaluate Systemic Exposure ». Proceedings for Annual Meeting of The Japanese Pharmacological Society 95 (2022) : 1—S08–1. http://dx.doi.org/10.1254/jpssuppl.95.0_1-s08-1.

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Poojari, Ambikaakshi Sriniwas, et V. Balasubramanian. « Age Estimation of Polymeric Insulation in Absorption of Chemical Components ». Indian Journal of Public Health Research & ; Development 8, n^o 3s (2017) : 134. http://dx.doi.org/10.5958/0976-5506.2017.00260.1.

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KINUGASA, HIDEYUKI, et SETSURO NOMUA. « DAMAGE ESTIMATION OF R/C MEMBERS BASED ON ENERGY ABSORPTION ». Journal of Structural and Construction Engineering (Transactions of AIJ) 384 (1988) : 68–79. http://dx.doi.org/10.3130/aijsx.384.0_68.

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