arXiv subjects

Pawel Rochowski

Publications and source records attributed to Pawel Rochowski.

5 recordsLinked to original sources

arXiv2026

Determination of the mass transport parameters in thin membranes by phase-sensitive photoacoustics in the optically transparent and mixed regimes

The research complements and extends the scope of the work reported in the article "LED-based multibeam photoacoustics combined with electrical circuit-based modeling for the analysis of multispecies mass transport through thin membranes" (arXiv:2602.20902). In particular, this work investigates the impact of the sample's absorption properties on the ability to quantify slow mass transport processes in thin membranes under optically transparent and semi-opaque conditions. The theoretical framework is based on the Green's function approach as formalized by Mandelis. Owing to the separation of photoacoustic and mass transport timescales, the heat distributions are assumed to follow the temporal mass concentration profiles predicted by a Fickian diffusion process. The approach is further examined and validated using experimental data on pigment transport into a thin porous membrane. Detailed experimental results are provided in the referenced paper.

physics.app-ph↗

arXiv2026

LED-based multibeam photoacoustics combined with electrical circuit-based modeling for the analysis of multispecies mass transport through thin membranes

This work develops photoacoustic-based experimental methods for comprehensive characterization of multispecies mass transport from donor compartments to thin-membrane acceptor systems in perfect contact, supported by a dedicated mass transfer modeling framework. Multibeam configurations are implemented in photoacoustic setups operating in front-side detection and diffuse-reflection geometries. The setups are calibrated and adjusted prior to measurements by means of transmission-mode photoacoustic experiments conducted under steady-state conditions. Finally, the methodologies were applied to a model system undergoing photoinduced decay, enabling characterization of bulk transport kinetics as well as interfacial equilibration monitored through time-dependent changes in interfacial reflectivity. For the analysis of bulk transport data, a lumped electrical-circuit (EC) model is introduced. The model is formulated in tableau form, linking species population dynamics to an interaction matrix representing mass-transport couplings consistent with the underlying diffusion-reaction framework. A simplified approximation of the model is further proposed and validated against experimental results. The combined experimental-modeling framework provides an effective approach for quantitative analysis of coupled diffusion, reaction, and interfacial processes in thin-membrane systems.

physics.app-ph↗

arXiv2025

A prelude to the multibeam photoacoustics

The research focuses on the introduction and validation of the lock-in photoacoustics of condensed systems in the presence of two simultaneous probing beams. The experiments, performed on three model systems: a perfect absorber - carbon black membrane, a multilayer system - acrylic coated copper plate, and a luminescent sample - ruby, were aimed at the comparative analysis of the frequency domain photoacoustic responses to a single probe beam (classical approach) and to two probe beams (of different wavelength). A modulation frequency shift criterion allowing the simultaneous acquisition of two independent signals was recognized. No synergistic or cross effects of the two-beam excitation on the photoacoustic signal generation (beam intensity effects or modulation frequency effects) were observed. The multibeam photoacoustic data appear to be (at least) equivalent to classically obtained results for stationary systems. It is expected that the multibeam approach will extend the applicability of photothermal methods to time-dependent systems, where the evolution of distinct absorption bands is of particular interest. An application of the developed method, related to the site-dependent energy storage efficiency of photosynthetically active samples, was described and validated on a three-beam experiment performed on a model Ficus benjamina L. leaf.

physics.app-ph↗

arXiv2023

On the equivocal nature of the mass absorption curves

The idea behind the research presented is based upon apparently contradictory experimental results obtained here by means of photoacoustics modalities for the same drug donor/acceptor membrane system, serving as a surrogate for a transdermal delivery system. The first modality allowed for the monitoring of the total amount of mass uptake (m(t)-type data), while the second technique allowed for the quantification of time-dependent concentration distribution within the acceptor membrane (c(x,t)-type data). Despite of a very good agreement between the m(t) data and the 1st-order uptake fitting model (standard Fickian diffusion with constant source boundary condition), the standard approach failed during the c(x,t) data analysis. The results led to the analysis of the interfacial transfer contribution to the overall mass transfer efficiency, which eventually allowed to question reliability of the m(t) data analysis for the determination and quantification of the mass transport parameters. A more detailed analysis of the c(x,t) by means of the newly introduced transport rate number parameter revealed, that the mass uptake by the acceptor is almost equally influenced by interfacial and bulk transport processes. The analyses performed were translated into a model-free characteristic times, i.e. parameters common for any of the model scheme used.

cond-mat.soft↗

arXiv2022

Mass diffusion in multilayer systems: an electrical analogue modelling approach

We develop a lumped parameter model to describe and predict the mass release of (absorption from) an arbitrary shaped body of any dimension in a large environment. Through the one-to-one analogy between diffusion-dominated mass transfer systems and electrical circuits we provide exact solutions in terms of averaged concentrations and mass released. An estimate of the release and characteristic time is also given. The proposed electrical analogue approach allows the definition of a time constant and lets an easy extension to a multi-layer and multi-phase cases. The simulation results are compared with those obtained from the solution of the corresponding analytical and numerical solutions, showing a good agreement.

physics.app-ph↗