Study of KBr/Pb(NO3)2 growth and crystal morphologies by acoustic emission and photomicrographic techniques

Plaster Hydration at Different Plaster-to-Water Ratios: Acoustic Emission and 3-Dimensional Submicrometric Simulations

“…The response of a solid to mechanical constraints such as crack propagation is usually considered as the main source of acoustic emission at these frequencies. However, phase transitions, liquid transfer in a porous material, , electrochemical reactions, and heterogeneous reactions , with gas bubble emission, , dissolution , or precipitation , are also known to be acoustically active. Here, the movement of domain boundaries due to dissolution of plaster grains and the collisions of solid particles with the beaker or with other particles due to gypsum needle growth are suspected to induce acoustic hits. − It is therefore assumed that the time evolution of the cumulative number of acoustic emission hits provides information on the kinetics of the heterogeneous reaction of interest.…”

Potassium- and Rubidium-Passivated Alloyed Perovskite Films: Optoelectronic Properties and Moisture Stability

“…The XRD pattern corresponding to the K-passivated samples exposed for 24 h also contains a weak reflection at 2θ = 8.9° that may correspond to a hydrated lead-passivated K bromide compound (e.g., KPbBr 3 ·H 2 0), 41 with the SEM-EDX showing the presence of K- and Br-rich needle-like crystals on the sample surface (Figure 5c); a precise chemical identification is not possible at this stage. 42…”

“…The XRD pattern corresponding to the K-passivated samples exposed for 24 h also contains a weak reflection at 2θ = 8.9°that may correspond to a hydrated lead-passivated K bromide compound (e.g., KPbBr 3 •H 2 0), 41 with the SEM-EDX showing the presence of K-and Br-rich needle-like crystals on the sample surface (Figure 5c); a precise chemical identification is not possible at this stage. 42 In Figure 5d−f, we analyze the changes in the primary perovskite peak at 2θ ≈ 14.1°(Figure 5d), the full width at half-maximum (FWHM) (Figure 5e), and the peak area (Figure 5f) for the films at different exposure times. We observe that for both Rb-and K-passivated TC films, the perovskite peak is shifted toward lower angles relative to the peak from the TC sample, which indicates expansion of the perovskite lattice and is in agreement with previous reports.…”

“…In Figure c, it is evident that similar PbI 2 and CsPb 2 I 4 Br reflections are present in the XRD data for the K-passivated TC sample albeit at much weaker intensities compared to the TC films. The XRD pattern corresponding to the K-passivated samples exposed for 24 h also contains a weak reflection at 2θ = 8.9° that may correspond to a hydrated lead-passivated K bromide compound (e.g., KPbBr 3 ·H 2 0), with the SEM-EDX showing the presence of K- and Br-rich needle-like crystals on the sample surface (Figure c); a precise chemical identification is not possible at this stage …”

Thermally induced acoustic emission from polycrystalline buckminsterfullerene

“…We report here the first observation of thermally induced AE in polycrystalline Cm in the temperature range 180-300 K. Intense AE occurs in a relatively narrow temperature interval T at about 260 K. As previous investigations have shown an orientational ordering phasetransition in solid Ca3. 4 at 260 K it is supposed that the observed AE is related to that phase transition.…”