Inverse Identification of Thermal Properties of Charring Ablators

Molavi, Hosein; Pourshaban, Iraj; Hakkaki-Fard, Ali; Molavi, Mehdi; Ayasoufi, Anahita; Rahmani, Ramin

doi:10.1080/10407790903508129

Cited by 34 publications

(6 citation statements)

References 29 publications

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“…In the general framework of flammability properties this approach has been seldom used [68,69] although it has recently received renewed attention [70][71][72][73][74][75][76]. Numerous similar efforts, though, exist in the literature mostly aimed at determining a limited set of thermal properties and for specific applications [77][78][79][80][81][82].…”

Section: Optimizationmentioning

confidence: 99%

“…As can be expected, the optimization problem is complex and highly non-linear. Therefore, local search methods such as direct search [83] and gradient search [84] algorithms are not applicable; however, such methods have been used widely for property estimation [68,69,77,81,82]. Global methods are needed which can tackle the major complications of high-dimensionality optimization such as local optima, multiple attraction basins, discontinuities, etc.…”

Section: Optimizationmentioning

confidence: 99%

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Combustion Characteristics of Materials and Generation of Fire Products

Khan

Tewarson

Chaos

2016

SFPE Handbook of Fire Protection Engineering

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Section: Optimizationmentioning

confidence: 99%

Section: Optimizationmentioning

confidence: 99%

Combustion Characteristics of Materials and Generation of Fire Products

Khan

Tewarson

Chaos

2016

SFPE Handbook of Fire Protection Engineering

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“…The initial concept of employing the 950 nm wavelength to monitor bladder volume was proposed by Macnab and then validated by Molavi et al, 23 first in vitro using a specially constructed phantom incorporating a fillable latex balloon to simulate the bladder, and then with an in vivo voiding study. The experimental NIRS prototype used a 950 nm LED (55 nm spectral half-width, 16 mw nominal power) driven by a constant current driver and a 5.22 mm silicone photodiode detector integrated with a transimpedance amplifier.…”

Section: Discussionmentioning

confidence: 99%

A wearable optical sensor monitoring bladder urine volume to aid rehabilitation following spinal cord injury

Macnab

Pourabbassi²,

Hakimi³

et al. 2023

Biophotonics in Exercise Science, Sports Medicine, Health Monitoring Technologies, and Wearables IV

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Background: Spinal cord injury (SCI) compromises bladder function, including the ability to sense the need to void. Overdistension leads to involuntary leakage and endangers health through upper renal tract pressure damage and autonomic dysreflexia. A monitor warning the bladder is full will allow optimal use of manual expression or intermittent catheterization. Methods: The wearable interface is a silicone sheet worn over the bladder, which incorporates a grid of 4 near-infrared LED transmitters with 3 wavelengths (2 at 950 nm for water detection and 2 of 760 and 850 nm for conventional monitoring of O2Hb and HHb). The system has 8 continuous-wave measurement channels and monitors at 2 different vertical levels to detect variation in bladder fullness; IOD’s of 30 and 40mm provide information at 2 depths. Associations between optical densities during bladder emptying and then during natural filling were compared. Results: Data from 4 male and one female subject were analyzed. The optical densities recorded at the lower vertical locations showed positive correlation with the voiding rate (ratio of scale signal), and O2Hb and HHb concentration changes at higher vertical locations revealed muscle activation prior to voiding. Discussion: This pilot study provides proof of the feasibility of using a 950nm wavelength incorporated into a wearable NIRS bladder monitoring system to transcutaneously and non-invasively detect changes in bladder volume in real-time. Conclusions: Ongoing research is warranted to further evaluate the system as the bladder fills naturally; and establish the clinical value of the data obtained to patients living with spinal cord injury

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“…However, high-frequency measurements noise significantly affect the quality of the results obtained with the inverse method. When the unknown parameters are constant (time and space), the adjoint functions are not necessary and the minimization may be performed with the sensitivity functions which simplifies the method [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Comparison of global and sequential methods for an inverse heat transfer problem

Marcos

Boulet

Ousegui

et al. 2011

Inverse Problems in Science and Engineering

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This article presents a comparison between global and sequential methods to solve inverse problem related to the baking process. Both methods aim to reconstruct the wall temperature profile in the baking oven from the temperature of flux sensor (h-Monitor). The global method solves the adjoint and sensitivity equations to compute the gradient conjugate descent direction. This method contains regularization term that modifies the computation of the gradient. The sequential method computes at each time step a quasi-Newton descent direction taking into account a regularization term. This method may consider one-step or some time steps to improve the descent direction. The comparison shows that both methods perform well. However, the global method is better for noisy data and the sequential method provides satisfying results which makes it an interesting approach because of its simplicity.

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Inverse Identification of Thermal Properties of Charring Ablators

Cited by 34 publications

References 29 publications

Combustion Characteristics of Materials and Generation of Fire Products

Combustion Characteristics of Materials and Generation of Fire Products

A wearable optical sensor monitoring bladder urine volume to aid rehabilitation following spinal cord injury

Comparison of global and sequential methods for an inverse heat transfer problem

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