Shock Damage Research Articles

An innovative approach to study the influence of microstructure on thermal shock resistance of porous ceramics

AbstractPorosity is a critical microstructural factor in ceramic materials, influencing their mechanical and thermal properties. However, the detailed mechanisms through which porosity, grain size, and grain boundary fracture energy affect the thermal shock resistance of porous ceramics are still not fully understood. This study introduces a dual‐scale model that integrates these microstructural parameters to predict fracture toughness and thermal shock resistance. Using the single‐edge V‐notch fracture toughness testing principle, we calculate the thermal stress intensity factor and establish its relationship with temperature differentials. The critical temperature differential, which marks the onset of thermal shock damage, is determined when the thermal stress intensity factor reaches the fracture toughness threshold. The model reveals a significant interplay between porosity, grain size, and grain boundary fracture energy, with fine‐grained ceramics (grain size < 10 µm) showing a sharp decrease in fracture toughness as porosity increases, while coarser‐grained ceramics are less affected by porosity. These findings provide a deeper understanding of the microstructural optimization needed to enhance the thermal shock resistance of high‐performance porous ceramics.

Experimental and modeling investigation of the thermal shock behavior of TiC-based self-healing coatings on AISI 321 stainless steel

The AISI 321 steels of structural components serviced at high temperature are usually subjected to oxidation and thermal shock damage during service. Therefore, to improve their high-temperature oxidation and thermal shock resistance, the self-healing coating consisting of Al2O3-13 %TiO2 layer, TiC layer and NiCrAlY layer was prepared for 321 steels in this work. The experimental and microstructural characterization results showed that the thermal shock resistance of such self-healing coating was remarkably improved as compared to the counterpart double-AT13 coating. This is because the volume increment resulting from the oxidation reaction between the TiC and oxygen decreased the porosity of the self-healing coating and retarded crack growth, which also led to the improved high-temperature oxidation resistance. Further, a thermal shock life model based on the crack growth model of Paris formula were developed. The modeling results not only agreed well with the experimental results but also indicated that thickening of thermal grown oxide (TGO) is the main cause of crack initiation and growth.

Grain-based coupled thermo-mechanical modeling for stressed heterogeneous granite under thermal shock

Microscopic damage and macroscopic mechanical properties of granite under the coupling effect of thermal load and initial stress are crucial considerations for the safe construction of underground geo-energy engineering. However, visualizing real-time micro-crack processes in rocks under high-temperature and high-pressure conditions using the current experimental techniques remains challenging. In this study, a numerical method is developed to analyze the thermally induced damage in heterogeneous granite under the coupled influence of initial stress and thermal loading. A biaxial thermo-mechanical grain-based model considering real mineral distribution is established based on digital image processing technology, the grain-based modeling method, and heat conduction theory. The microscopic parameters are calibrated and the effectiveness of the model is verified based on thermal shock and uniaxial compression experiments. The thermal destruction mechanism of granite under initial stress from a microscopic perspective was unveiled for the first time. During the thermal shock process, the stress within the rock does not remain constant at the initial stress value. Instead, it changes continuously with the progression of heat conduction. The impact of the initial stress on the thermally induced cracks is relatively minor. Cooling causes more damage to the rock than heating during thermal shock. The intragranular cracks of quartz consistently outnumber other intragranular or intergranular cracks during thermal shock. The initial stress and thermal shock damage enhance and weaken the biaxial peak strength of granite, respectively. The weakening effect of thermal shock on the peak strength becomes more pronounced at a higher initial stress. These research findings and proposed research techniques contribute to the management and optimization of underground geo-energy engineering.

Boar Sperm Performance in Polystyrene Transport Cool Box Under Various Storage Conditions and Holding Times

When transporting highly valuable boar semen samples over long distances, it is crucial to ensure that boar semen is stored ideally at approximately 15 – 17°C to minimize the impact of cold shock and oxidative damage on sperm quality. This study evaluated the performance of a commercially available semen and embryo polystyrene transport cool box, BotuFLEX®, in preserving the quality of extended boar semen under different storage conditions and holding times. Boar ejaculates were extended at 1:1 or 1:3 using a commercial mid-term extender, stored in a BotuFLEX® semen cool box, and examined 24 vs. 48 h thereafter (Experiment 1; n = 12), or 24 h after storage in air-conditioned room vs. ambient room (Experiment 2; n = 9) conditions. Comprehensive sperm motility using the Sperm Class Analyzer® CASA system revealed no significant difference in either total and progressively motile sperm, and the combined progressivity and velocity characteristics across different treatments. Almost similar results were observed on sperm vitality using the standard supravital staining technique except that percent live spermatozoa were higher at 24 h of storage using the 1:1 dilution.

Thermophysical-mechanical behaviors of hot dry granite subjected to thermal shock cycles and dynamic loadings

Exploring dynamic mechanical responses and failure behaviors of hot dry rock (HDR) is significant for geothermal exploitation and stability assessment. In this study, via the split Hopkinson pressure bar (SHPB) system, a series of dynamic compression tests were conducted on granite treated by cyclic thermal shocks at different temperatures. We analyzed the effects of cyclic thermal shock on the thermal-related physical and dynamic mechanical behaviors of granite. Specifically, the P-wave velocity, dynamic strength, and elastic modulus of the tested granite decrease with increasing temperature and cycle number, while porosity and peak strain increase. The degradation law of dynamic mechanical properties could be described by a cubic polynomial. Cyclic thermal shock promotes shear cracks propagation, causing dynamic failure mode of granite to transition from splitting to tensile-shear composite failure, accompanied by surface spalling and debris splashing. Moreover, the thermal shock damage evolution and coupled failure mechanism of tested granite are discussed. The evolution of thermal shock damage with thermal shock cycle numbers shows an obvious S-shaped surface, featured by an exponential correlation with dynamic mechanical parameters. In addition, with increasing thermal shock temperature and cycles, granite mineral species barely change, but the length and width of thermal cracks increase significantly. The non-uniform expansion of minerals, thermal shock-induced cracking, and water-rock interaction are primary factors for deteriorating dynamic mechanical properties of granite under cyclic thermal shock.

Reliability analysis of multi-component systems subjected to dependent degradation processes and random shocks in dynamic environments

This article presents reliability models for multi-component systems subjected to multiple internally dependent degradation processes and external shocks in dynamic environments. We use the homogeneous semi-Markov process (HSMP) to describe the evolution of the environment state and the non-homogeneous Poisson process (NHPP) to model the arrival of shocks. The degradation processes of the system components are modeled using either general path models (GPM) or stochastic processes. The models highlight the shock-induced degradation acceleration, the degradation-shock dependence, and the influence of dynamic environments on the degradation processes and shock damage. The integrated process evolution (i.e., system degradations, shock arrivals, and environment shifts) follows a non-homogeneous Markov renewal process (NHMRP) in a multidimensional space. The NHMRP semi-Markov kernel and theoretical formulation for system reliability are derived. We provide a simulation algorithm to estimate system reliability. Finally, we demonstrate the theoretical correctness and applicability of the model using a micro-electro-mechanical system (MEMS).

A modular model for reliability analysis model of PMS with multiple K/N subsystems and mixed shocks

AbstractIn this article, a modular model is proposed for the reliability modeling of phased mission systems (PMSs) with complicated system behaviors. By the modular method, the system is divided into several levels: system, subsystem, and components. At the component level, the shock effect, including self‐degradation, additional wear and damage caused by shocks, is considered and the component reliability is evaluated. Then, the reliability modeling method of the K/N system consisting of multiple K/N subsystems is proposed, by a mathematics reasoning method. The correctness of the proposed method is also verified by a Monte Carlo (MC) simulation procedure. At last, the modular method is applied at the system level, and the reliability of a practical engineering case, the attitude and orbit control system (AOCS), is evaluated for illustration. Meanwhile, the parameter sensitivity analysis is also carried out for implementation.

The use of X-Ray computed tomography for the diagnosis of composite structures in the energy sector

RELEVANCE In modern Russia, an important condition for the development of the Far North and Far Eastern regions is to provide these regions with electricity. In remote areas with increased wind potential, the use of wind power plants, the main structural elements of which are made of polymer composite materials (PCM), is promising. The most dangerous operational defect of the PCM is shock damage: due to hail strikes or pieces of ice that broke off during heating of the blades, as well as lightning strikes. Such defects, which are difficult to detect during visual inspection, can significantly reduce the strength and service life of the structure. At the stages of technology development and design certification, the use of modern methods of non-destructive testing is required.PURPOSE. To evaluate the possibilities of X-ray computed tomography for the diagnosis of structural elements made of PCM with impact damage.METHODS. After applying a low-speed impact to fragments of the blades of the wind turbine, a visual inspection and measurement of the size of internal injuries are carried out on a Phoenix V |Tome|X X-ray computed tomograph.RESULTS The nature of the damage inflicted with different impact energies on the most critical areas of fragments of the airfoil blades and the stringer panel is investigated. The depth and area of damage have been determined. The nature and size of internal injuries were studied using an X-rayCOMPUTED tomograph. conclusion. The results obtained allow us to estimate with high accuracy the size and location of impact damage, which can be used in strength calculations.

Abstract 3093: Can Inhibiting Ferroptosis And Subsequent Endothelial Glycocalyx Shedding Reduce The Morbidity And Mortality Of Hemorrhagic Shock?

Background: Trauma patients with hemorrhagic shock accounts for 40% of preventable death. Shock-induced endotheliopathy has garnered interest recently and one aspect of this, endothelial glycocalyx shedding, has shown to promote coagulopathy following hemorrhage. Ferroptosis is an iron dependent, non-apoptotic form of controlled cell death triggered by the oxidation of membrane phospholipids. Liproxstatin-1 (LPX1) is an inhibitor of this process and can protect against oxidative damage to the endothelial cell membrane and subsequent shedding of glycocalyx. We hypothesized that LPX1 would reduce endothelial glycocalyx damage in hemorrhagic shock. Methods: A rat model of hemorrhagic shock and resuscitation was used to assess glycocalyx disruption in the lungs via fluorescent-labeled wheat germ agglutinin staining in frozen tissue and by Syndecan-1 ELISA on plasma samples. A control group (n=5) resuscitated only with Lactated Ringer’s solution, following hemorrhage and resuscitation (H/R) was compared against an experimental group (n=5) that received LPX1 following hemorrhage and before resuscitation. Results: Glycocalyx shedding (assessed by an increase in plasma Syndecan-1 levels) was prevented in the LPX1 treated group compared to control group. Lung tissue staining of the glycocalyx also showed a greater glycocalyx level in the LPX1 group than in the control (40.4 vs 36.3 arbitrary units). Additionally, LPX1 treated animals were able to sustain a higher mean arterial pressure (82 vs 45mmHg), and oxygen saturation throughout the resuscitation period measured at 15 and 30 minutes following LPX1 infusion (98.4% SpO2 vs. 99.0% SpO2 at 30 minutes resuscitation). Conclusions: Ferroptosis inhibitor LPX1 can reduce morbidity acutely during hemorrhagic shock and can protect the endothelial cell glycocalyx from oxidative damage due to its ability to slow the generation of reactive oxygen species and lipid hydroperoxides.

An integrative warning-protection shear thickened composite sponge towards sensing performance and impact resistance with excellent flame retardant

The mechanical shock and thermal damage generally exist together in hazardous environment, whereas traditional single protective materials are difficult to achieve all-round protection under extreme environment. Herein, to realize the integration of multifunctional abilities about impact resistance, flame-retardant and sensing performance, a “solid-liquid host-guest” structural shear thickened composite sponge is proposed, which flame-retardant shear thickening fluids with an extraordinary thickening ratio of 2183.95 % continuously disperse in 3D sponge matrix. The resulting composite sponge effectively attenuates the impact force by nearly 80 % with the thickness of only 4 mm via a cooperation between the effect of shear hardening and structure densification. Meanwhile, after burning on the alcohol flame for 12 s, the composite sponge with 7 wt.% fire-retardant additive maintains a complete morphology and realizes self-extinguishing with a reliable flame-retardant ability. Attributed to the good electrical conductivity of shear thickening fluid, the composite sponge serves favorably in human body monitoring, impact sensing and fire warning. In a word, this multifunctional lightweight composite sponge is expected to realize the integration of early warning and protection, which is a competitive candidate material for the intelligent protection in complex environments.

Our Experience in Using Extracorporeal Membrane Oxygenation in Patients with Refractory Cardiogenic Shock

Background Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is a critical care treatment option for patients with refractory cardiogenic shock. This method of temporary support of the cardiorespiratory system gives us and the patient time to restore organ function or is a «bridge» to other methods of treatment. Nevertheless, the issue of identifying the optimal time for VA ECMO implantation in patients with acute myocardial infarction complicated by refractory cardiogenic shock remains relevant.Aim To evaluate the efficiency of extracorporeal membrane oxygenation in various clinical situations in patients with acute myocardial infarction complicated by refractory cardiogenic shock and post-infarction damage to the valves of the heart.Material and method We present 3 patients with acute coronary syndrome complicated by refractory cardiogenic shock, of different age groups and comorbidities, who underwent veno-arterial extracorporeal oxygenation in various SCAI shock stages, and mechanical complications associated with acute myocardial infarction.Results In all the cases, stabilization of hemodynamics and heart function was achieved, and there were no hypoxic disorders of organs. In one case, a hemorrhagic complication associated with the VA ECMO procedure was noted. In one case, VA ECMO was performed as an intermediate stage for the correction of post-infarction mitral valve injury.Conclusion These clinical cases demonstrate the efficiency of the timely start of VA ECMO before the development of organ dysfunction, which allows restoring myocardial function, and helps maintain hemodynamic normalization before the cardiac surgical stage of treatment.

Mechanism and Prevention of Main Roadway Roof Shock in Strong-Bump Coal Seam with Asymmetric Goaf

In response to the increasingly severe situation of main roadway shock in coal seams, with a focus on the strong-bump coal seam in main roadways under an asymmetric goaf in a certain mine, theoretical analysis, numerical simulation, and engineering practices were employed. This study investigated factors influencing main roadway roof shock damage, changes in roof stress, and characteristics of overlying strata movement. This research unveiled the mechanism and prevention of roof shock in main roadways of strong-bump coal seams in an asymmetric goaf. The research results indicate that the influencing factors of main roadway roof shock damage can be divided into two categories: “strata-support” structure strength and surrounding rock stress. For the determination of the “strata-support” structure, in the case of strong bumps in coal seam roadways influenced by the asymmetric goaf, the key factors contributing to shock damage are the side abutment pressure on the coal pillar in the goaf and the activity level of the roof strata. The distribution of roof stress in the main roadway undergoes continuous changes as district faces are sequentially mined. When the goaf area on the west side gradually increases towards the south, the roof stress in the main roadway consistently rises, and the stress increment follows a pattern of initial increase followed by a decrease. The strata structure of the main roadway roof gradually transforms from an “asymmetric T” shape to a “symmetric T” shape in the transverse profile, and with the evolution of the roof rock layer structure, the mutual feedback effect of strata activity on both sides of the roadway gradually strengthens. Affected by the asymmetric goaf, the main roadway in the district undergoes three different stages: one side of subcritical mining influence → both sides of subcritical mining influence → one side of subcritical mining and one side of critical mining influence. In addition, comprehensively considering the impact of various factors in different stages, the theoretical criteria for roof shock failure in the main roadway are determined. The formulation of an optimized position for the main roadway and a scheme for depressurization through deep-hole blasting in the roof reduce the stress level in the surrounding rock of the main roadway, effectively preventing the occurrence of roof shock in the asymmetric goaf of the coal seam main roadway.

Microstructure, mechanical properties and thermal shock behavior of 2.5D oxide fiber preform reinforced oxide matrix composites

The 2.5D oxide/oxide composites become attractive for their excellent integrity and mechanical properties. The thermal shock resistance performance of the material is very important in the actual high temperature application. In this work, the evolution of microstructure and mechanical behavior of the 2.5D oxide/oxide composites from thermal shock at different temperatures and cycles was investigated experimentally mainly by optical microscope, X-ray computed tomography and macro-mechanical tests. The thermal shock resistance mechanism of oxide/oxide composites was qualitatively explored. The results showed that cracks propagation was the main manifestation of thermal shock damage in composites. Compared with 2D composites, 2.5D composites exhibited the finite domain effect on crack propagation due to its reinforcement had certain fibers in Z-direction. This directly caused the critical thermal shock temperature difference of the 2.5D composites (∼900 °C) was more than twice that of the 2D oxide/oxide composites (∼400 °C). In addition, the finite domain effect also significantly reduced the damage growth rate of the 2.5D composites from cyclic thermal shock, highlighting its excellent thermal shock damage resistance.

On Survival of Coherent Systems Subject to Random Shocks

We consider coherent systems subject to random shocks that can damage a random number of components of a system. Based on the distribution of the number of failed components, we discuss three models, namely, (i) a shock can damage any number of components (including zero) with the same probability, (ii) each shock damages, at least, one component, and (iii) a shock can damage, at most, one component. Shocks arrival times are modeled using three important counting processes, namely, the Poisson generalized gamma process, the Poisson phase-type process and the renewal process with matrix Mittag-Leffler distributed inter-arrival times. For the defined shock models, we discuss relevant reliability properties of coherent systems. An optimal replacement policy for repairable systems is considered as an application of the proposed modeling.

Shock fatigue damage failure boundary study of BGA solder joints based on shock response spectrum

Multiple shock damage failure of ball grid array (BGA) solder joints is one of the important reasons for reusable spacecraft mission failure. Shock fatigue damage failure boundary of BGA solder joints is proposed based on shock response spectrum (SRS), which can be used to assess the damage failure state. Weibull distribution is employed to characterize the shock fatigue life for a specified SRS. A Bayesian estimation method based on the Bootstrap approach is proposed to estimate Weibull distribution parameters. By using the time-domain load synthesized method based on wavelet and the experimentally validated shock fatigue life model, the shock fatigue life data of BGA solder joints corresponding to different SRS are extended. The variation patterns of the scale and shape parameters with the SRS parameters is analyzed. Then the shock fatigue damage failure boundary based on SRS is determined for a given design life and reliability. The results show that the critical SRS amplitude increase with the rise of the inflection point frequency and the low-frequency slope, respectively. The developed method is expected to provide references for the environment-adaptive design of BGA solder joints in reusable spacecraft.

Вплив амфіфільних сполук на форму та ериптоз еритроцитів людини в умовах постгіпертонічного шоку

The search for protective substances that can be used during red blood cell thawing and the study of their effects on red blood cells contribute to increasing the number and quality of viable cells after the cryopreservation cycle. We studied the effect of posthypertonic shock and amphiphilic compounds on the shape and eryptosis of human erythrocytes. The method of flow cytometry was used, this allows analyzing two parameters simultaneously, which increases the efficiency of research. The shape was assessed by the sphericity index (SphI), and eryptosis by the redistribution of phosphatidylserine to the membrane outer surface. It has been shown that sodium decylsulfate and chlorpromazine reduce erythrocyte damage in posthypertonic shock by 3.6 and 4.2 times, respectively. Sodium decylsulfate helps to preserve the shape of cells (SphI coefficient remains the same), while when chlorpromazine is used, the shape changes towards spherical (SphI coefficient changes 2 times). The study of the level of Annexin V FITC binding to phosphatidylserine in outer layer of membrane revealed a concentration-dependent increase in fluorescence when sodium decylsulfate was used, indicating a disorder of the bilayer asymmetry. In contrast, chlorpromazine did not change the distribution of phosphatidylserine. Comparison of two parameters of cell viability - the sphericity coefficient and anexin binding - allowed us to choose the conditions that are optimal for the use of the studied protective substances. Namely, it is advisable to use the lowest effective concentration of sodium decylsulfate (200 mcmol/l) for protective purposes. This ensures the preservation of the cell shape and minimal impact on the membrane asymmetry.

Revealing thermal shock behaviors and damage mechanism of 3D needled C/C–SiC composites based on multi-scale analysis

Understanding thermal shock behaviors and related damage mechanism of needled C/C–SiC composites is of much significance to their engineering application. In this study, a multi-scale framework is developed to characterize the degeneration of mechanical properties and damage accumulation in the needled composites comprehensively across different scales under cyclic thermal shock. Thermal shock temperature and thermal shock cycles are involved in the simulation, and the outcomes are verified with experiments performed in an inert atmosphere. The results show that the strength of C/C–SiC composites decreases continuously as the test temperature and thermal shock cycles increase. Meanwhile, the fracture of the material mainly occurs in the short-fiber felt. The damage initiates in the short-fiber felt near the contact area of the non-woven (NW) fiber tow and the needle-punched (NP) fiber tow when the test temperature is low (about 900 °C), and gets severe as temperature increases. With the increase of thermal shock cycles at 1700 °C, the fracture of the composites is more significant, and spreads from inside to the outer surface. Based on the multi-scale simulation and the microstructure of the composites after TSR tests, the primary damage mechanisms in the short-fiber felt are identified as ceramic-matrix damage and interface debonding.

Investigating the structural and mechanical behavioral properties of semi-organic nonlinear optical single crystal: L-arginine tetrafluoroborate

A semi-organic nonlinear optical material L-Arginine tetrafluoroborate (LAFB) was synthesized as single crystal using Slow Evaporation Technique. Various properties of this material were analyzed to make it suitable for NLO applications. The structural behavior of the material was determined by single crystal XRD and found that the crystal has orthorhombic structure and was synthesized with P212121 space group. The High-Resolution X-Ray Diffraction (HRXRD) study was conducted to determine the change in the lattice parameters resulting from strain, defects or by other means in LAFB material. The diffraction curve analysis show that the grown crystal consisted of interstitial type point defect. The Shock Damage Threshold (SDT) measures the stability of the compound against shock, the analysis exhibits that under Mach number 2.2 up to 10th shock no significant cracks were observed in the crystal but damage area of the crystal was increased. The mechanical behavior of the sample against highly intense laser was analyzed through Laser Damage Threshold (LDT). The calculated value of LDT was to be 0.75[Formula: see text]GW/cm2 for 1 pulse per second whereas it decreased to 0.57[Formula: see text]GW/cm2 for 10 pulse per second. To explore the mechanical properties of the material, Nano indentation was carried out, by which the values of H[Formula: see text][Formula: see text]MPa and E[Formula: see text][Formula: see text]GPa were obtained.

Calycosin Enhances Heat Shock Related-Proteins in H9c2 Cells to Modulate Survival and Apoptosis against Heat Shock.

Heat shock proteins (HSPs), which function as chaperones, are activated in response to various environmental stressors. In addition to their role in diverse aspects of protein production, HSPs protect against harmful protein-related stressors. Calycosin exhibits numerous beneficial properties. This study aims to explore the protective effects of calycosin in the heart under heat shock and determine its underlying mechanism. H9c2 cells, western blot, TUNEL staining, flow cytometry, and immunofluorescence staining were used. The time-dependent effects of heat shock analyzed using western blot revealed increased HSP expression for up to 2[Formula: see text]h, followed by protein degradation after 4[Formula: see text]h. Hence, a heat shock damage duration of 4[Formula: see text]h was chosen for subsequent investigations. Calycosin administered post-heat shock demonstrated dose-dependent recovery of cell viability. Under heat shock conditions, calycosin prevented the apoptosis of H9c2 cells by upregulating HSPs, suppressing p-JNK, enhancing Bcl-2 activation, and inhibiting cleaved caspase 3. Calycosin also inhibited Fas/FasL expression and activated cell survival markers (p-PI3K, p-ERK, p-Akt), indicating their cytoprotective properties through PI3K/Akt activation and JNK inhibition. TUNEL staining and flow cytometry confirmed that calycosin reduced apoptosis. Moreover, calycosin reversed the inhibitory effects of quercetin on HSF1 and Hsp70 expression, illustrating its role in enhancing Hsp70 expression through HSF1 activation during heat shock. Immunofluorescence staining demonstrated HSF1 translocation to the nucleus following calycosin treatment, emphasizing its cytoprotective effects. In conclusion, calycosin exhibits pronounced protective effects against heat shock-induced damages by modulating HSP expression and regulating key signaling pathways to promote cell survival in H9c2 cells.

PH-Assisted multichannel heat shock monitoring in the endoplasmic reticulum with a pyridinium fluorophore.

Heat shock is a global health concern as it causes permanent damage to living cells and has a relatively high mortality rate. Therefore, diagnostic tools that facilitate a better understanding of heat shock damage and the defense mechanism at the sub-cellular level are of great importance. In this report, we have demonstrated the use of a pyridinium-based fluorescent molecule, PM-ER-OH, as a 'multichannel' imaging probe to monitor the pH change associated with a heat shock in the endoplasmic reticulum. Among the three pyridinium derivatives synthesized, PM-ER-OH was chosen for study due to its excellent biocompatibility, good localization in the endoplasmic reticulum, and intracellular pH response signaled by a yellow fluorescence (λ max = 556 nm) at acidic pH and a far red fluorescence (λ max = 660 nm) at basic pH. By changing the excitation wavelength, we could modulate the fluorescence signal in 'turn-ON', single excitation ratiometric and 'turn-OFF' modes, making the fluorophore a 'multichannel' probe for both ex vitro and in vitro pH monitoring in the endoplasmic reticulum. The probe could efficiently monitor the pH change when heat shock was applied to cells either directly or in a pre-heated manner, which gives insight on cellular acidification caused by heat stress.