BIM-Sim: Interactive Simulation of Broadband Imaging Using Mie Theory

Berisha, Sebastian; Dijk, T. van; Bhargava, Rohit; Carney, P. Scott; Mayerich, David

doi:10.1017/s1431927616008035

Cited by 3 publications

(3 citation statements)

References 26 publications

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“…For the radiative part, the model by Wang et al (2017a) is used as explained previously. The complex refractive index of the PMMA matrix is approximated as 1.47 + 0.02i for the most pertinent wavelength of 10 mm of room temperature thermal radiation (Berisha et al, 2016). The cell wall thickness is deduced from the 3D image of the generated samples by a distance transformation algorithm and is weight-averaged by the cell wall area.…”

Section: Property Valuementioning

confidence: 99%

A 3D model to predict the influence of nanoscale pores or reduced gas pressures on the effective thermal conductivity of cellular porous building materials

Walle

Janssen

2019

Journal of Building Physics

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Cellular porous materials are frequently applied in the construction industry, both for structural and insulation purposes. The progressively stringent energy regulations mandate the development of better performing insulation materials. Recently, novel porous materials with nanopores or reduced gas pressures have been shown to possess even lower thermal conductivities because of the Knudsen effect inside their pores. Further understanding of the relation between the pore structure and the effective thermal conductivity is needed to quantify the potential improvement and design new optimized materials. This article presents the extension of a 3D numerical framework simulating the heat transfer at the pore scale. A novel methodology to model the reduced gas-phase conductivity in nanopores or at low gas pressures is presented, accounting for the 3D pore geometry while remaining computationally efficient. Validation with experimental and numerical results from the literature indicates the accuracy of the methodology over the full range of pore sizes and gas pressures. Combined with an analytical model to account for thermal radiation, the framework is applied to predict the thermal conductivity of a nanocellular poly(methyl methacrylate) foam experimentally characterized in the literature. The simulation results show excellent agreement with less than 5% difference with the experimental results, validating the model’s performance. Furthermore, results also indicate the potential improvements when decreasing the pore size from the micrometre to the nanometre range, mounting up to 40% reduction for such high-porosity low-matrix-conductivity materials. Future application of the model could assist the design of advanced materials, properly accounting for the effect of reduced pore sizes and gas pressures.

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Section: Property Valuementioning

confidence: 99%

A 3D model to predict the influence of nanoscale pores or reduced gas pressures on the effective thermal conductivity of cellular porous building materials

Walle

Janssen

2019

Journal of Building Physics

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“…We first test the viability of the proposed technique using a Mie scattering forward model that utilizes both coherent and incoherent sources [30,31]. We approximate the absorbance image produced by a set of neighboring spheres with varying absorption values (Fig.…”

Section: Simulationmentioning

confidence: 99%

Mitigating fringing in discrete frequency infrared imaging using time-delayed integration

Ran¹,

Berisha²,

Mankar³

et al. 2018

Biomed. Opt. Express

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Infrared (IR) spectroscopic microscopes provide the potential for label-free quantitative molecular imaging of biological samples, which can be used to aid in histology, forensics, and pharmaceutical analysis. Most IR imaging systems use broadband illumination combined with a spectrometer to separate the signal into spectral components. This technique is currently too slow for many biomedical applications such as clinical diagnosis, primarily due to the availability of bright mid-infrared sources and sensitive MCT detectors. There has been a recent push to increase throughput using coherent light sources, such as synchrotron radiation and quantum cascade lasers. While these sources provide a significant increase in intensity, the coherence introduces fringing artifacts in the final image. We demonstrate that applying time-delayed integration in one dimension can dramatically reduce fringing artifacts with minimal alterations to the standard infrared imaging pipeline. The proposed technique also offers the potential for less expensive focal plane array detectors, since linear arrays can be more readily incorporated into the proposed framework.

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“…There is now an emerging understanding of the physics underlying spectral distortions associated with scattering of IR radiation from samples with spherical, 28,29 cylindrical, 30 thin film, 31–37 or more complex geometry. 38–40 The forward problem of predicting IR spectra, given the shape and properties of the sample, is now generally well described for a variety of cases.…”

Section: Introductionmentioning

confidence: 99%

Extended Multiplicative Signal Correction for Infrared Microspectroscopy of Heterogeneous Samples with Cylindrical Domains

et al. 2019

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Optical scattering corrections are invoked to computationally distinguish between scattering and absorption contributions to recorded data in infrared (IR) microscopy, with a goal to obtain an absorption spectrum that is relatively free of the effects of sample morphology. Here, we present a modification of the extended multiplicative signal correction (EMSC) approach that allows for spectral recovery from fibers and cylindrical domains in heterogeneous samples. The developed theoretical approach is based on exact Mie theory for infinite cylinders. Although rigorous Mie theory implies utilization of comprehensive and time-consuming calculations, we propose to change the workflow of the original EMSC algorithm to minimize extensive calculations for each recorded spectrum at each iteration step. This makes the modified EMSC approach practical for routine use. First, we tested our approach using synthetic data derived from a rigorous model of scattering from cylinders in an IR microscope. Second, we applied the approach to Fourier transform IR (FT-IR) microspectroscopy data recorded from filamentous fungal and cellulose samples with pronounced fiber-like shapes. While the corrected spectra show greatly reduced baseline offsets and consistency, strongly absorbing regions of the spectrum require further refinement. The modified EMSC algorithm broadly mitigates the effects of scattering, offering a practical approach to more consistent and accurate spectra from cylindrical objects or heterogeneous samples with cylindrical domains.

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BIM-Sim: Interactive Simulation of Broadband Imaging Using Mie Theory

Cited by 3 publications

References 26 publications

A 3D model to predict the influence of nanoscale pores or reduced gas pressures on the effective thermal conductivity of cellular porous building materials

A 3D model to predict the influence of nanoscale pores or reduced gas pressures on the effective thermal conductivity of cellular porous building materials

Mitigating fringing in discrete frequency infrared imaging using time-delayed integration

Extended Multiplicative Signal Correction for Infrared Microspectroscopy of Heterogeneous Samples with Cylindrical Domains

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