Real-Time Monitoring of the Surface Modification of Root Dentin Using MIR-FEL-Induced Acoustic Waves

For non-invasive laser dental treatmet, a real-time and non-contact monitoring technique is needed. We have investigated the extent of the surface modification of root dentin using photoacoustic spectroscopy (PAS) and pulsed-photothermal radiometry (PPTR), and have discussed the applicability of each technology to in vivo monitoring during laser treatment. Root dentins were used as specimens. The wavelength, average power density, and exposure time used were varied within the ranges λ = 9.0-10.6 μm, P av = 7-28 W/cm 2 , and τ = 0-10 s respectively. The temporal behaviors of the laser-induced acoustic waves and the temperature rise were measured with an audible microphone and a radiation thermometer, respectively. The extent of the surface modification was evaluated by using information on the ablation depth and the absorption spectrum of the irradiated dentin. The morphological and chemical changes of the irradiated dentin can be made available to assist in dentinal tubule sealing and increased acid resistance for root surface caries therapy. It was found that time-resolved measurements of the acoustic waves and the temperature are useful for a real-time understanding of the extent of the morphological and chemical changes, respectively. We have demonstrated that applicability of an in vivo monitoring technique using PAS and PPTR for root surface caries therapy.

This research article summarizes results from Part 1 of a study designed to examine using advanced signal processing techniques with acoustic-based lumber assessment technologies to evaluate the MOE, ultimate tension stress (UTS), and MOR of structural lumber. In Part 1 of this research article, a mathematical model of acoustic wave behavior in an idealized specimen is derived using fundamental mechanics. Published information on the physical and mechanical properties of clear, defect-free wood is input into the model to examine acoustic wave behavior. Wave behavior is then examined experimentally in a series of wood specimens. Observed wave behavior in the clear wood specimens, in both time and frequency domains, closely resembles idealized wave behavior. In Part 2 of this research article, predictions from the model are used to improve estimation of the UTS of wood specimens.

Real-time plasma monitoring technique using incident-angle-dependent optical emission spectroscopy for computer-integrated manufacturing

Monitoring Solid-Substrate fermentations by Fourier Transform Infrared-Photoacoustic Spectroscopy

The morphological and chemical changes in deciduous dentin produced by different conditioning protocols were evaluated in this in vitro study. Eighty primary dentin samples were divided into eight groups (n = 10): G1, acid etching; G2, self-etching adhesive; G3, G4, Er: YAG laser irradiation at 25.5 and 38.2 Jcm-2 , respectively; 10 Hz and spray irrigation. Groups 5, 6, 7, and 8 were irradiated at previous densities, and then phosphoric acid or self-etching adhesive conditioning was applied. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to evaluate chemical and morphological changes. Paired t-test and One-way ANOVA were used for statistical analysis (p ≤ 0.05). All samples showed different morphology with specific characteristics according to the conditioning protocol. Changing element concentration values are expressed in atomic percent (at %). After conditioning, there were statistically significant differences (p ≤ 0.05) for p at% and Ca/P in all groups; highlighting the following additional findings by group: G1, G7, and G8 showed changes in all elements studied, G2 presented a decrease in C at% and increased Ca at%, G3 and G4 exhibited at% changes in C, trace elements and Ca. Furthermore, G5 showed at% changes in O and trace elements; while G6 changes were observed on C at%, O at% and trace elements at%. Dentin morphology and chemical composition varied in accordance with the conditioning protocol, with characteristics specific for each one that could have clinical implications for the retention and bond strength performance of adhesive materials.

The recent work of Sardar et al. [Phys. Plasmas 23, 073703 (2016)] on the existence and stability of the small amplitude dust ion acoustic solitary waves in a collisionless unmagnetized plasma consisting of warm adiabatic ions, static negatively charged dust grains, isothermal positrons, and nonthermal electrons due to Cairns et al. [Geophys. Res. Lett. 22, 2709 (1995)] has been extended by considering nonthermal electrons having a vortex-like velocity distribution due to Schamel [Plasma Phys. 13, 491 (1971); 14, 905 (1972)] instead of taking nonthermal electrons. This distribution takes care of both free and trapped electrons. A Schamel's modified Kadomtsev Petviashvili (SKP) equation describes the nonlinear behaviour of dust ion acoustic waves in this plasma system. The nonlinear behaviour of the dust ion acoustic wave is described by the same Kadomtsev Petviashvili (KP) equation of Sardar et al. [Phys. Plasmas 23, 073703 (2016)] when B = 0, where B is the coefficient of nonlinear term of the SKP equation. A combined SKP-KP equation more efficiently describes the nonlinear behaviour of dust ion acoustic waves when B → 0. The solitary wave solution of the SKP equation and the alternative solitary wave solution of the combined SKP-KP equation having profile different from both sech4 and sech2 are stable at the lowest order of the wave number. It is found that this alternative solitary wave solution of the combined SKP-KP equation and its lowest order stability analysis are exactly the same as those of the solitary wave solution of the KP equation when B → 0.

Evaluation of porous poly(lactide-co-glycolide) scaffold surface-modified by irradiation of nitrogen ion beams

Metal-based energy storage systems (ESS)—including lithium, sodium, magnesium, and zinc batteries—are indispensable for sustainable energy applications. Yet, they often suffer from material degradation, unsafe dendrite growth, and ineffective ion transport. This study introduces a novel nanoscience-enhanced photoacoustic spectroscopy (PAS) framework to tackle these challenges with quantitative rigor. PAS, which converts modulated light absorption into acoustic waves, has been shown to image lithium metal dendrites in 3D with micrometer resolution (~3 µm) and penetration depths of ~160 µm. When applied to layered nanomaterials—e.g., MoS₂ reduced from 112 to 7 µm thickness—the PAS signal improves by nearly 50×. Similarly, metal nanoparticle aggregates exhibit distinct PAS signatures, enabling the determination of aggregate size distributions and packing density. Integrating these findings, our work synthesizes evidence from battery-specific PAS studies, highlighting 3D dendrite detection, phase-change monitoring, SEI layer growth, and hotspot identification. We detail synthesis methods (sol–gel, hydrothermal, CVD) and PAS instrumentation (532 nm pulsed laser, piezoelectric detectors, modulation cells) to ensure reproducibility. Comparative analysis shows that nanomaterial-augmented PAS enhances diagnostic sensitivity ~24× over planar electrodes and lowers detection limits by ~4×—a trend consistent with sensor literature. We present case studies with spectral maps and quantitative metrics supporting material engineering interventions like doping, morphology control, and coating. Finally, we discuss ambitions to integrate PAS operando with AI/ML analytics for predictive diagnostics, addressing limitations like depth penetration and instrumentation complexity. This convergence of nanoscience and PAS provides a transformative blueprint for real-time, data-driven optimization of metal-based ESS, aiming at enhanced performance, safety, and longevity.

This is the first of a two-part series on the chemical, morphological, and electrical changes of polydimethylsiloxane (PDMS) and alumina trihydrate (ATH) material system subjected to dry-band discharges produced on the material surface by sustained moisture and contamination buildup. This system possesses both stable hydrophobicity restricting water-film formation as a path of leakage current and high resistance to electrically conductive path (track) formation induced by dry-band discharges, contributing to the recent innovation of polymeric outdoor insulation technology. The PDMS/ATH system has been believed to be resistant to track formation (tracking). However, it was observed in the present study that the PDMS/ATH system occasionally allows track formation leading to a dielectric breakdown in an internationally standardized tracking test, with the carbon concentrations in the formed track being measured at a mere /spl sim/1% wt. The unknown phenomenon of tracking of the PDMS/ATH system was studied here from the perspective of chemical structure and of electrical insulation. This first paper describes the chemical and morphological changes of the PDMS/ATH system subjected to dry-band discharges. A comparison with the thermal decomposition behavior of the PDMS/ATH system heated in the presence and absence of oxygen was carried out to better our understanding of the tracking mechanism. Amorphous SiO/sub 2/ and mullite 3Al/sub 2/O/sub 3/.2SiO/sub 2/ were primarily produced by the dry-band discharges, while cristobalite SiO/sub 2/ and mullite 3Al/sub 2/O/sub 3/.2SiO/sub 2/ were produced by thermal decomposition in either air or nitrogen gas. Cristobalite SiO/sub 2/ and mullite 3Al/sub 2/O/sub 3/.2SiO/sub 2/ are basic ingredients of ceramic insulators, which may contribute to recycling of the PDMS/ATH system. The structure of carbon deposited in the track was not absolute graphite, and its concentration was much higher than that of the heated system. Finally, we propose herein models of the chemical changes induced by dry-band discharges as well as heat treatments.

Lithium-ion batteries (LIBs) capable of safe and reliable cycling at a fast-charge rate (i.e., >2C or <30 minutes to full charge) will have a direct impact on today’s consumer technology by improving the utility of portable electronics and reducing the barrier for widespread adoption of electric vehicles. However, at high charge rates, the long-term battery performance suffers because of heterogeneous reactivity across both electrodes (e.g., lithium metal plating on the anode surface, fracture of the cathode particles, etc.) [1]–[3]. A fundamental study of the processes responsible for battery degradation is a necessary step toward designing next-generation LIBs and is a critical research priority for the U.S. Department of Energy. Here, we demonstrate that high charging currents lead to chemical, structural, and morphological changes in the graphite anode that spans the atomic-scale to the bulk-scale. As the integrity of the graphite host is critical to lithium-ion cell performance, our findings regarding the degradation mechanism provide the essential knowledge to enable the development of viable fast-charging LIBs.Our strategies to study the graphite anode degradation are based on advanced analytical electron microscopy and diffraction. We focus on the modifications that occur in the material when subjected to charging rates up to 6C (i.e., 10 minutes to full charge). The characterization is performed post-mortem across different length-scales on as-prepared electrodes and electrodes harvested from cycled cells (represented in Figure 1). At the bulk-scale, we use scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to probe the morphological and chemical changes in cross-sections of the graphite anode samples. At the nano- and atomic-scale, we use advanced transmission electron microscopy (TEM) and diffraction techniques to reveal changes in both the nano-scale chemistry and the graphite microstructure. Key findings from this investigation include the morphological changes to the graphite particles at the micron-scale and the partial-filling of the inter- and intra-particle gaps with solid electrolyte interphase (SEI) compounds at the meso-scale. Further, at the nano- to atomic-scale, we observe greater disorder and amorphous character in the graphite near the internal pore surfaces when compared to that of the bulk graphite regions. The nature of the lattice disorder, and the characterization methods employed to examine this disorder, will be discussed. Additional supporting evidences of graphite disorder and phase change from Raman spectroscopy and X-ray diffraction studies will also be presented. Acknowledgements: SP acknowledges support from the U.S. Department of Energy Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the U. S. Department of Energy under contract number DE‐SC0014664. This work was carried out in part in the Materials Research Laboratory Central Research Facilities, University of Illinois. DA and MTFR acknowledge support from DOE’s Vehicle Technologies Office. This document has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. References : [1] C. Heubner, K. Nikolowski, S. Reuber, M. Schneider, M. Wolter, and A. Michaelis, “Recent Insights into Rate Performance Limitations of Li-ion Batteries,” Batter. Supercaps, Nov. 2020.[2] M.-T. Fonseca Rodrigues et al., “Lithium Acetylide: A Spectroscopic Marker for Lithium Deposition During Fast Charging of Li-Ion Cells,” ACS Appl. Energy Mater., vol. 2, no. 1, pp. 873–881, Jan. 2019.[3] Y. Yang et al., “Quantification of Heterogeneous Degradation in Li-Ion Batteries,” Adv. Energy Mater., vol. 9, no. 25, p. 1900674, Jul. 2019. Figure 1

Adsorption processes have a wide range of applications in environmental science and materials research. Understanding the surface morphology and elemental composition of bioadsorbents is fundamental for assessing their effectiveness in these processes. In this study, we utilized advanced analytical techniques, including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Fourier Transform Infrared Spectroscopy (FTIR), to investigate the structural and chemical changes that occur in bioadsorbents before and after cocoon adsorption. Raily cocoon, Daba BV, and Daba TV were selected as model bioadsorbents for this comprehensive analysis. This research paper investigates the surface morphology and chemical composition changes in tasar cocoons, specifically Raily cocoon, Daba BV, and Daba TV, before and after the adsorption process. The analysis was conducted using Scanning Electron Microscopy (SEM) to observe the morphological changes, and Energy Dispersive X-ray Spectroscopy (EDS) to determine the elemental composition. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR) was employed to identify functional groups in the tasar cocoon components. The results reveal significant surface modifications and elemental interactions, shedding light on the adsorption capacity of tasar cocoons.

This paper focuses on the evaluation of the treatment related to chemical and morphological changes of corroded lead artifacts when using electrolytic reduction as a stabilization method. Synchrotron radiation X-ray diffraction and X-ray photoelectron spectroscopy were used to study the chemical changes of the corrosion layer and on the top nanometer of surface, respectively. Neutron tomography and scanning electron microscopy were used to visualize potential morphological changes on millimeter and micrometer level, respectively. The results of this study have shown that electrolytic reduction is a reliable way to stabilize and conserve active corroded lead artifacts. The corrosion products are actually converted into metallic lead, while the morphological changes due to the treatment are limited.

Infrared spectroscopy using semiconductor lasers is a promising technique for trace gas detection. It allows a continuous and real time monitoring of several species, with a high sensitivity and a good selectivity. Among all the possible methods two are particularly suitable for this application: wavelength modulation spectroscopy (WMS) based on an optical detection of the transmitted light intensity and photoacoustic spectroscopy, which detects an acoustic wave produced by the energy absorbed in the sample. Semiconductor lasers are easily modulated through their injection current and are thus well suited for these applications. The laser modulation is a key issue for these techniques and is first described in detail, both theoretically and experimentally. Experimental methods used to determine the modulation parameters are presented. Then, a theoretical model describing the interaction of a modulated optical wave with an absorption line is exposed. Two different cases are considered. In the first, the modulation frequency is higher than the width of the absorption line, whereas it is smaller in the second. In this latter case, the developed model takes into account the simultaneous intensity (IM) and frequency (FM) modulation of the laser. This establishes a generalization of existing models, which consider only the FM modulation and thus imperfectly describe the real laser behavior. A more exact model was obtained by taking into account the laser intensity modulation and the results are confirmed with a remarkable precision by experimental measurements. The effect of several modulation parameters on the measured signals was studied from this theoretical model and is validated by numerous experimental results. A new experimental method was developed on the basis of this model to measure the modulation parameters of a laser. The obtained results correspond with a good precision to the values supplied by other traditional methods, which demonstrates the validity of this new technique. The two experimental techniques for trace gas detection were implemented using a DFB semiconductor laser emitting at λ = 2 µm for CO2 monitoring. In the WMS method, the laser emission frequency was actively stabilized on a CO2 absorption line, which reduced its relative frequency fluctuations below 10-7. The photoacoustic spectroscopy was implemented using a resonant acoustic cavity, operated in its first radial mode in order to optimize the photoacoustic effect efficiency. Both intensity and frequency modulations of the laser were applied and their performances were compared. In our experimental configurations, the WMS method showed the best sensitivity, with a detection limit lower than 1 ppm × m. Several solutions are proposed to increase the performances of each method, taking into account their own specificity. It turns out that the WMS method has a better sensitivity in the near infrared, where very sensitive photodetectors are available. But, its performances decrease with increasing wavelength, as the photodetectors sensitivity strongly decreases. On the other hand, photoacoustic spectroscopy has the advantage to be totally wavelength-independent, as the detection is made acoustically. Thus, it becomes more attractive than WMS in the mid-infrared, especially when taking advantage of high power lasers available in this spectral range. Finally, the potential of a new kind of semiconductor lasers is estimated for trace gas detection. These so-called quantum cascade lasers were invented some years ago and operate at room-temperature in the mid-infrared. A characterization of their main optical properties is exposed and some spectroscopic measurements are shown.

Quantitative analysis of glucose using conventional optical spectroscopy suffers from a lack of repeatability due to high optical scattering in skin tissue. Here we present a multi-modality analysis of glucose aqueous solution using photoacoustic spectroscopy (PAS) and broadband dielectric spectroscopy (BDS). These techniques involve the direct detection of the acoustic and electromagnetic waves propagating through or reflecting from tissue without their being scattered. They therefore have potential for better tolerance to the variation of scattering. For PAS, to differentiate signals induced by water absorption, we select another laser wavelength (1.38 μm) that exhibits the same absorbance for water at 1.61 μm. Furthermore, one of the two photoacoustic signals is used to normalize the variations of acoustic properties in differential signal. Measured results for glucose solutions (0–2 g/dL) showed that the differential signal has a sensitivity of 1.61%/g·dL−1 and a detection limit of 120 mg/dL. We also tested glucose detection with BDS (500 MHz to 50 GHz) by detecting glucose hydration bonding at around 10-20 GHz. Using a partial least square analysis and first derivation on broadband spectra, we obtained an RMS error 19 mg/dL and a detection limit of 59 mg/dL. Using both the low-scattering ultrasonic and microwave detection techniques, we successfully captured the glucose footprint in the physiological range.

This research is focused on measuring the dispersion behavior of acoustic wedge waves propagating along the tip of circular wedges with a laser-generation/laser-detection laser ultrasound technique. The unexpected measurement results indicate that the dispersion relation of the fundamental antisymmetric flexural (ASF) mode has a negative slope in the phase velocity-frequency dispersion space for a nearly truncation-free circular wedge. It is also observed that, at the low-frequency, or long-wavelength limit, the fundamental ASF mode of the circular wedge has a phase velocity higher than that of a straight wedge due to the curvature effect. However, at the high-frequency, or short-wavelength limit, the fundamental ASF mode of the circular wedge becomes insensitive to the curvature effect and is dominated by the truncation effect.