Residual Damage Research Articles

Microcirculatory resistance after primary percutaneous coronary intervention predicts residual myocardial damage: a post hoc analysis from the CLEVER-ACS trial

Abstract Introduction Coronary microvascular dysfunction has been associated with adverse cardiovascular events following acute myocardial infarction. This study evaluates the role of the angiography-derived index of microcirculatory resistance (angio-IMR) in predicting myocardial damage in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Material and Methods In this post hoc analysis of the Controlled Level Everolimus in Acute Coronary Syndromes (CLEVER-ACS) trial, the associations between post-PCI angio-IMR of infarct-related coronary arteries (IRAs) and infarct size, microvascular obstruction (MVO), and left ventricle ejection fraction (LVEF) at 30 days as assessed with cardiac magnetic resonance (CMR) imaging were investigated. High post-PCI angio-IMR value was defined as a value >40 U. In non-IRAs angio-IMR was measured before the IRA-PCI. Results A total of 52 IRAs and 94 non-IRAs of 52 patients were included in the analysis. Post-PCI Angio-IMR was 41.5 (IQR 28.5–55.7) U in IRAs and pre-PCI Angio-IMR was 43.7 (31.7–54.0) U in non-IRAs (p = 0.70). Patients with high post-PCI angio-IMR (52%) exhibited a larger myocardial infarct size (36.0 [23.0–52.5] g vs. 14.5 [6.50–26.5] g, p < 0.001) and a lower LVEF (46.5 [39.5–49.5] % vs. 55.0 [48.0–61.4] %, p = 0.002) at 30 days as compared to those with low post-PCI angio-IMR values. Post-PCI angio-IMR correlated with myocardial infarct size (r = 0.45, p = 0.001) and extent of MVO (r = 0.40, p = 0.004) at 30 days. Post-PCI angio-IMR predicted myocardial infarct size (AUC = 0.78 [0.65–0.92], p = 0.001) and extent of MVO (AUC = 0.74 [0.60–0.89], p = 0.009) at 30 days. Conclusion In patients with STEMI undergoing PCI, post-PCI angio-IMR was identified as independent predictor of myocardial infarct size and extent of MVO at 30 days. The assessment of post-PCI angio-IMR values may represent a novel tool for early risk stratification of patients with STEMI.Central illustration

Residual behaviour and damage assessment of UHPC-filled double-skin steel tubular columns after lateral impact

Ultra-high performance concrete (UHPC)-filled double-skin steel tubular (DST) column has great potential to be used in the protective structures. Although its lateral impact behaviour has been well understood, the residual behaviour after lateral impact remains unexplored. As a result, this study extensively investigated the residual behaviour and damage assessment of UHPC-filled DST columns after lateral impact. Firstly, a set of six DST columns were designed and tested under lateral impact, followed by static axial compression. In addition, two intact columns were subjected to static axial compression for comparative analysis. Secondly, the refined finite element models were developed and validated using the current test data, and the impact resistant mechanism of UHPC-filled DST columns with different impact locations was analysed. Thirdly, the suitability of different damage indexes for the damage assessment of impacted UHPC-filled DST columns was evaluated. Two damage indexes, the ratio of mid-height deflection to column height (R1), and the ratio of local deflection to the column diameter (R2), were proposed for the DST columns. Finally, two types of machine learning-based models were developed to predict the impact damage of UHPC-filled DST columns. The prediction models were interpreted locally and globally using the additive feature attribution method Shapley Additive Explanation (SHAP). The machine learning-based prediction models can rapidly evaluate the damage extent of impacted UHPC-filled DST column, which hold great significance for the selection of strengthening and retrofitting schemes.

Investigation of Residual Strength in CFRP Double-Adhesive Single Lap Bonded Joints after Low-velocity Impact

ABSTRACT Single lap adhesive joints are prone to debonding and delamination during impact, affecting the residual tensile strength and mechanical properties. To improve the stress distribution and withstand larger loads, this paper proposes to use Araldite 2015 ductile adhesive at both ends of the joint and AV 138 brittle adhesive in the middle. Through finite element analysis and experiments, the residual strength and damage of the joint under different impact conditions are investigated, and a three-parameter Gram-Charlier model is established. The results show that the model can fit the data points accurately with a coefficient of determination of error above 0.99. As impact energy increases, the residual strength of the joint decreases, especially the AV 138 joint is more sensitive. The residual strength on one side of the impact joint is approximately 20% higher compared to the middle of the impact joint. For the same energy, the residual strength of the secondary impact was about 13% higher than that of the single impact. The main failure mode is cohesive failure, which gradually changes to fiber tear. The numerical simulation matches the experimental results, which verifies the reliability of the simulation and analysis methods.

Blast-Induced Progressive Collapse Analysis: Accounting for Initial Conditions and Damage

The paper presents the progressive collapse analysis of structures, focusing on the impact of the initial conditions (particularly initial velocity) and the damage. It proposes a method that calculates the residual axial load capacity and damage of columns based on their strain profile and considers the effects of multiple blast locations. The methodology involves the conventional design of a three-story moment-resisting frame, selecting blast parameters, calculating blast pressures, and performing structural and progressive collapse analyses. The findings reveal that the Alternate Load Path Method (APM) overestimates the capacity compared to a benchmark blast–structure interaction analysis, especially when unsuitable initial conditions and damage properties are used. To address this limitation, the paper concludes the recommendations for incorporating appropriate initial conditions and damage considerations for a relatively accurate progressive collapse analysis.

Mutagenicity of the agriculture pesticide chlorothalonil assessed by somatic mutation and recombination test in Drosophila melanogaster.

Chlorothalonil (CTL) is a pesticide widely used in Brazil, yet its mutagenic potential is not fully determined. Thus, we assessed the mutagenicity of CTL and its bioactivation metabolites using the somatic mutation and recombination test (SMART) in Drosophila melanogaster, by exposing individuals, with basal and high bioactivation capacities (standard and high bioactivation cross offspring, respectively), from third instar larval to early adult fly stages, to CTL-contaminated substrate (0.25, 1, 10 or 20 μM). This substrate served as food and as physical medium. Increased frequency of large single spots in standard cross flies' wings exposed to 0.25 μM indicates that, if CTL is genotoxic, it may affect Drosophila at early life stages. Since the total spot frequency did not change, CTL cannot be considered mutagenic in SMART. The same long-term exposure design was performed to test whether CTL induces oxidative imbalance in flies with basal (wild-type, WT) or high bioactivation (ORR strain) levels. CTL did not alter reactive oxygen species and antioxidant capacity against peroxyl radicals levels in adult flies. However, lipid peroxidation (LPO) levels were increased in WT male flies exposed to 1 μM CTL. SMART and LPO alterations were observed only in flies with basal bioactivation levels, pointing to direct CTL toxicity to DNA and lipids. Survival, emergence and locomotor behavior were not affected, indicating no bias due to lethality, developmental and behavioral impairment. We suggest that, if related to CTL exposure, DNA and lipid damages may be residual damage of earlier life stages of D. melanogaster.

Damage assessment of self‐centering rocking piers using an input energy‐based damage prediction model coupled with self‐centering index

AbstractThe immediate functionality of bridges following severe earthquakes is vital for uninterrupted rescue operations. Regarding the significance of resiliency in bridges, post‐tensioned (PT) rocking piers with low residual displacements and minimal damages have developed over the past few decades. The rocking mechanism at two ends of the pier avoids bending moments and excessive flexural damage. The self‐centering (SC) capacity in this system is provided through post‐tensioning forces. Concerning optimum seismic design and retrofit purposes, it is essential to predict the actual degree of seismic damage and SC capacity of PT rocking systems after seismic hazards. In this case, a self‐centering index (SI) is proposed to evaluate the SC capacity when piers are subjected to cyclic and seismic loadings. This SI, when used in co‐operation with a viable damage prediction model, predicts whether or not the piers remain reparable under cyclic or seismic loading scenarios. After comparing a number of energy‐based damage indices, all of which consider the cumulative hysteresis energy, with the input energy‐based damage index (IEB‐DI), the latter was calibrated against observed damages under cyclic loading tests. This DI was chosen as the most suitable damage prediction model and was considered to be simply applicable after time history analysis. In this study, the seismic performance of a seismic‐resistant dual system, consisting of three RC bents along with an SC bent, was evaluated using the aforementioned damage limit states and the introduced SI. The damage predictions of the monolithic bridge, as the reference model, were compared with the estimated damage to the dual bridge. The results show that the joint application of the IEB‐DI and the proposed SI in predicting the performance level of SC rocking piers results in a comprehensive damage prediction model.

Evaluating Personalized Add-On Ayurveda Therapy in Oxygen-Dependent Diabetic COVID-19 Patients: A 60-Day Study of Symptoms, Inflammation, and Radiological Changes.

Background Effective management of both acute and post-acute sequelae of SARS-CoV-2 is essential, particularly for type 2 diabetes mellitus (T2DM) patients, who are at increased risk of severe pro-inflammatory responses and complications. Persistent symptoms and residual lung and cardiovascular damage in post-coronavirus disease (COVID-19) individuals highlight the need for comprehensive long-term treatment strategies. Conventional treatments, including Remdesivir and glucocorticoids, have limitations, suggesting that further investigation into Ayurvedic therapies could be beneficial, though controlled trials are currently limited. Objectives Evaluate the effectiveness and safety of Ayurveda with the standard of care (SOC) versus SOC in improving symptoms, moderating immune responses (interleukin-6 (IL-6), C-reactive protein (CRP), neutrophil-lymphocyte ratio (NLR), and radiological outcomes in oxygen-dependent, high-risk, non-vaccinated type 2 diabetes COVID-19 patients over 60 days, and thus addressing their heightened vulnerability to severe infections. Methods A controlled trial with 50 diabetic COVID-19 patients, aged 18-80, with an NLR of >= 4, primarily on Remdesivir, was assigned to Group 1 (Add-on Ayurveda+SOC, n=30) or Group 2 (SOC, n=20) based on their voluntary choice with follow-up on days 14, 28, and 60. Parametric outcomes in group analysis were assessed with robust regression and non-parametric outcomes with Cochran-Mantel-Haenszel, log-rank test, and chi-square tests at 95% confidence interval (CI). Results Group 1 exhibited statistically significant improvements in fever, cough, diarrhea, as well as NLR, IL-6, and CRP by 14 days, and in anosmia, loss of taste, shortness of breath, general weakness, and headache by 60 days. Though the sample size is small, notable improvements can be seen in troponin levels in Group 1 at 28 and 60 days. High-resolution computer tomography COVID-19 reporting and data system (HRCT CO-RADS) scores improved more slowly in Group 2 than in Group 1. Survival rates were 96.4% for Group 1 and 90% for Group 2. Numbers were too small for reliable comparisons at 60 days. Conclusion The add-on Ayurveda group showed a better symptomatic response, and faster normalization in inflammatory markers, including IL-6 and NLR by 14 days, and cardiac markers by 28 days. Minimal clinical and no laboratory adverse events were observed. This study supports the need for a randomized, double-blind trial.

An experimental and numerical investigation of ballistic penetration behaviors of deployable composite shells

Bistable composite shells are suitable candidates for deployable space structures due to high stiffness to weight ratio as well as large volume reduction. Nevertheless, impact performance of bistable composite shells conflicting with space debris have been rarely studied. In this paper deployable hybrid composites constructed with combinations of carbon–carbon, carbon–kevlar, kevlar–kevlar, high-energy-absorption graphene-reinforced polyurethane elastomers are developed, and their ballistic penetration behaviors are experimentally and computationally studied. The influences of ballistic velocity on the absorbed energy, the residual velocity and damage morphology of the targets are investigated in both deployed and coiled stable states. The results show that severe local damages were observed for the carbon–carbon and carbon–kevlar samples after penetration with various velocities even first cosmic velocity, and the sample of deployable hybrid composite shell yielded the best ballistic impact resistance. The total energy absorption performance of the hybrid composite structure was greatly improved by introducing graphene-reinforced polyurethane elastomers without losing the deployability. Additionally, investigation on the energy absorption capability of deployed laminated shells with various curvature radii indicated that the curvature radius had a significant effect on the anti-penetration performance.

MitoTam induces ferroptosis and increases radiosensitivity in head and neck cancer cells

Background and purposeRadiotherapy (RT) is an integral treatment part for patients with head and neck squamous cell carcinoma (HNSCC), but radioresistance remains a major issue. Here, we use MitoTam, a mitochondrially targeted analogue of tamoxifen, which we aim to stimulate ferroptotic cell death with, and sensitize radioresistant cells to RT. Materials and methodsWe assessed viability, reactive oxygen species (ROS) production, disruption of mitochondrial membrane potential, and lipid peroxidation in radiosensitive (UT-SCC-40) and radioresistant (UT-SCC-5) HNSCC cells following MitoTam treatment. To assess ferroptosis specificity, we used the ferroptosis inhibitor ferrostatin-1 (fer-1). Also, total antioxidant capacity and sensitivity to tert-butyl hydroperoxide were evaluated to assess ROS-responses. 53BP1 staining was used to assess radiosensitivity after MitoTam treatment. ResultsOur data revealed increased ROS, cell death, disruption of mitochondrial membrane potential, and lipid peroxidation following MitoTam treatment in both cell lines. Adverse effects of MitoTam on cell death, membrane potential and lipid peroxidation were prevented by fer-1, indicating induction of ferroptosis. Radioresistant HNSCC cells were less sensitive to the effects of MitoTam due to intrinsic higher antioxidant capacity. MitoTam treatment prior to RT led to superadditive residual DNA damage expressed by 53BP1 foci compared to RT or MitoTam alone. ConclusionMitoTam induced ferroptosis in HNSCC cells, which could be used to overcome the elevated antioxidant capacity of radioresistant cells and sensitize such cells to RT. Treatment with MitoTam followed by RT could therefore present a promising effective therapy of radioresistant cancers.Statement of significance.Radiotherapy is applied in the treatment of a majority of cancer patients. Radioresistance due to elevated antioxidant levels can be overcome by promoting ferroptotic cell death combining ROS-inducing drug MitoTam with radiotherapy.

Impacts and effectiveness of sidewall treatment on the spatially resolved optical properties and efficiency enhancement for GaN-based blue and green micro-LEDs

InGaN-based micro-light-emitting diodes (micro-LEDs) are crucial for efficient full-color micro-displays, but suffer from severe degradation of external quantum efficiency (EQE) with size reduction. In this study, the impacts of chemical treatment on the sidewall condition and the EQE of the 10 μm InGaN-based blue and green micro-LEDs were demonstrated. The sidewall treatment can effectively alleviate the residual damage caused by dry etching and suppress the nonradiative recombination, facilitating the achievement of high internal quantum efficiency (IQE). Nevertheless, the sidewall light extraction of the micro-LEDs with smoother sidewall morphology after tetramethylammonium hydroxide (TMAH) treatment is lower than those with rough and prismatic sidewall surface. By utilizing microscopic hyperspectral imaging, the difference in chromatic properties between the inner region and the whole micro-LED caused by dry etching can hinder the stability of chromatic properties of InGaN-based blue micro-LEDs, which can be alleviated by sidewall treatment. The optimal duration for TMAH treatment is obtained as 10 min for both blue and green micro-LEDs, which is the consequence of the compromise between sidewall light extraction efficiency (LEE) and IQE, whereas the improvement of IQE by sidewall treatment for green micro-LEDs is less significant compared to that for blue ones, which can be attributed to the higher dislocation density and recombination via localized states of green InGaN micro-LEDs. This work demonstrates the evolution of IQE and LEE for blue and green micro-LEDs with different sidewall treatment strategies to achieving the ultimate EQE.

Temperature-dependent electron–phonon coupling changes the damage cascades in neutron-irradiation molecular dynamics simulation in W

We present a first-principles-based electron-temperature model that can be used in atomistic calculations. The electron–phonon coupling coefficient in the model is derived from the density of states as a function of electron temperature, and the thermal conductivity of tungsten from our model shows significant improvement over the baseline atomistic calculations in which only ion-thermal contribution to the thermal conductivity is available. The correction to the thermal conductivity also changes damage cascades as cascades cool down more rapidly within our model. The mobility of defects is consequently reduced, leaving more residual damage than the predictions without an electron-temperature model.

Development of self-sensing cement composites by incorporating hybrid biochar and nano carbon black

The self-sensing cement composites (SSCC) containing traditional conductive carbon materials are of great significance but cause serious pollution. In this study, the green SSCC is innovatively developed utilizing the synergistic effects of nano carbon black and biochar from coconut shell. The SSCC mixtures are compared in terms of fluidity, mechanical properties, resistivity, microstructure and comprehensive properties. The results indicate that in SSCC containing nano carbon black, the addition of biochar can obtain comparable compressive strength for its internal curing, interlocking and bridging effects. Besides, 4.5 % carbon material prolongs the crack initiation stage during compression, and 9 % carbon material causes the multiple cracks. Moreover, the addition of 4.5 % biochar can reduce the 35-day resistivity of sample with 1.5 % biochar and 3 % nano carbon black by 35.6 % owing to the increasing tunneling effect and contact conduction. It is also found that in conductive SSCC, the slope Kc of the non-contact resistivity curve is dominated by the conductive additives rather than cement hydration. And the self-sensing cement composites exhibit excellent piezoresistivity. The rates of change in resistivity of samples after cycle loading are exponentially related to residual damages, with R2 values greater than 0.95. Finally, multi-indicator evaluation analyses show that the sample containing more biochar is more environmentally friendly. This study provides a new pathway for the sustainable development of SSCC.

Optimizing sheet metal edge quality with laser-polishing: surface characterization and performance evaluation

Dual-phase (DP) steels are widely used in the automotive industry due to their exceptional performance. It offers excellent strength, ductility, formability, and weldability. However, there is a high risk of edge cracking, particularly in materials like DP1000 steel, caused by residual damage from blanking, such as microcracks and burrs, which needs further investigation. In this study, the transformative potential of laser-polishing on DP1000 steel was investigated. The goal was to reduce edge crack sensitivity and enhance edge formability. In this work, laser-polished samples produced by various pre-manufacturing techniques such as sawing, punching, and waterjet cutting were examined. Various evaluations were performed on laser-polished samples. Those included white-light-confocal microscopy, scanning electron microscopy, and Electron Backscatter Diffraction (EBSD) analysis. Those evaluations aimed to analyze the microstructural transformation, surface roughness, and micro grain size distribution resulting from laser-polishing. Laser-polishing is a process in which the edge of the sample is remelted locally. Hence, residual damage vanishes, and surface defects disappear, which should be beneficial for edge formability. On the other hand, the cooling rate during re-solidification is high, leading to high strength and reduced ductility compared to the initial DP steel. Therefore, hole expansion tests were conducted to evaluate the edge formability of the steel. The results indicated a significant improvement in the hole expansion ratio of the laser-polished samples compared to samples with conventional manufactured edges. These findings will help to assess the advantages and limitations of laser-polishing in sheet material manufacturing.

Filling the blindspots: Assessing distributive equity in fund allocation of Florida's local housing program for disaster recovery

Despite the role of local assistance in addressing households' disaster recovery needs, few studies have examined the role of localized programs in filling the gaps that might exist in federal programs. To address the question of whether local recovery funds distribute resources to socially vulnerable neighborhoods and how local assistance fits into the broader federal disaster assistance landscape, we take Florida's State Housing Initiatives Partnership (SHIP) program as a case study. The SHIP program can help fill neighborhood-level gaps left by the Federal Emergency Management Agency's (FEMA) Individual Assistance program by aiding neighborhoods with the higher proportions of 1) those who did not receive federal assistance or 2) those who had residual damages not fully covered by federal assistance. The study finds that SHIP funds typically flow into socially vulnerable neighborhoods with a higher proportion of Black and Hispanic residents, even without specific social or racial equity measures built into program regulations. The study highlights the importance of balancing the consistency of fundamental rules and having flexibility in distributing funds.

Gut Mucosal Immunity in HIV-Exposed Infants: A Review

Gut mucosal immunity in infants exposed to Human Immunodeficiency Virus (HIV) presents a complex interplay of developmental processes, viral dynamics, and therapeutic interventions that significantly impact clinical outcomes. This review synthesizes current knowledge on the mechanisms, clinical implications, and therapeutic strategies concerning gut mucosal immunity in HIV-exposed infants. The gut mucosa serves as a critical site for immune maturation and defense against pathogens, but HIV infection disrupts this delicate balance, leading to compromised immune function and increased susceptibility to infections. Infants born to HIV-positive mothers experience unique challenges in gut mucosal immunity due to vertical transmission of the virus and exposure to antiretroviral therapy (ART). HIV infection disrupts gut-associated lymphoid tissue (GALT), resulting in early depletion of CD4+ T cells and compromised mucosal barrier function. These alterations contribute to microbial translocation, chronic inflammation, and immune dysregulation, impacting overall immune competence and increasing susceptibility to opportunistic infections. Despite advances in ART, persistent immune activation and residual gut mucosal damage pose ongoing challenges in achieving optimal immune reconstitution and preventing long-term complications in HIV-exposed infants. Clinical implications of compromised gut mucosal immunity in HIV-exposed infants extend beyond gastrointestinal health to encompass systemic immune dysfunction and increased risks of non-AIDS comorbidities. Impaired gut barrier function exacerbates microbial translocation, leading to systemic inflammation that may contribute to neurodevelopmental abnormalities and metabolic disorders. Keywords: Gut, Immunity, HIV, Infants

Numerical investigation of residual stress and strain in blades caused by foreign body impact. Comparison of impact modeling on real blade and flat surface

Damage caused by the impact of a foreign object on the turbine blades is caused by the entry of millimeter-sized foreign particles such as sand, stones, or small pieces of broken parts. Consequently, the remaining damage resulting from the impact of a foreign body on the blades is in the form of geometrical discontinuities such as craters or grooves on the blades, which create suitable conditions for the creation and growth of cracks and the complete failure of the blades. One of the most important aspects of foreign body impact damage is the study of the resulting residual stresses at the impact site, which plays a significant role in the creation and growth of cracks. In the present article, the main aim of this work was to analyze the residual stresses due to foreign object damage by expanding the simulation on the blades, considering a real blade model as well as the leading-edge curvature effect. To validate the numerical modeling, the impact of a spherical particle on a flat plate was modeled and the residual stresses and damages resulting from the modeling were compared to the experimental results available in the articles. Finally, the impact of the spherical foreign body on different places of the leading edge of a blade with different impact velocities was investigated. Moreover, the examined blade sample was replaced with a plate with the same material, and the impact of the foreign object on the flat surface was modeled for two different service temperatures. In this study, the resulting residual stresses and strains in three critical areas were compared.

A Study on Effect Analysis and Process Parameter Optimization of Viscous Acid Acidification in a Porous Heterogeneous Carbonate Reservoir

The homogeneous acid etching of conventional acid in porous heterogeneous carbonate reservoirs leads to a large amount of consumption in the near-wellbore area, which makes the acidification effect often not ideal. In order to improve the acidizing effect of porous heterogeneous carbonate reservoirs, viscous acid is used to increase the stimulation of the target block in this paper. Through systematic experiments, the adaptability of the viscous acid in the four layers of the M reservoir in the target block was evaluated, and the MD and ME layers suitable for acidizing stimulation were determined in combination with physical property analysis. Finally, based on the geological characteristics and experimental data of the preferred layers, a two-scale acid wormhole growth radial model was established, and the construction parameters of acidizing stimulation were optimized. The results show that (1) The preferred viscous acid system has a dissolution rate of more than 95% for the rock powder in the four layers. When the matrix permeability is high, the effect of the acid wormhole is obvious and the permeability increase is higher. (2) The steel sheet corrosion and residual acid damage experiments showed that the acid system was not corrosive to the wellbore, and the reservoir damage rate of the residual acid after the reaction was low. (3) Based on the relationship between reservoir porosity and permeability and the position of edge and bottom water, the MD and ME layers with more potential for acidizing stimulation are selected. (4) The results of the numerical simulation show that the optimal acid pump rate of the MD and ME layers is 1.4 bpm and 1.0 bpm, and the acidizing fluid volume is 255 bbl, which can form effective acid wormholes, and the range of reservoir permeability transformation is the largest. The field application results show that the optimization scheme effectively improves the production of oil wells, verifies the practicability of the scheme, and provides a reference for the process optimization of viscous acid in the same type of porous heterogeneous carbonate reservoir stimulation.

The quantitative study of residual acid damage of low permeability carbonate rock based on NMR test

The Leikoupo carbonate reservoirs in the West Sichuan gas field generally exhibit low porosity and permeability characteristics. After acidizing, the fluid flowback rate is only 46%, and a large amount of residual acid remains in the reservoir, causing damage to the pores. In this study, the rheological tests were first carried out to reveal the rheological characteristics of fresh and residual acid with different thickener contents. Then, the change in core permeability before and after acid flooding was tested by core-flood tests, and the effects of acid on pore structure in various scales were analyzed in nuclear magnetic resonance (NMR) tests. The research results show that the average viscosity of residual acid increased to about 157.14% of the fresh acid and exhibited large viscosity fluctuations, which may be caused by the formation of aggregates combined with thickener and insoluble. The change rate of core permeability (both improvement and damage) decreased with the increase in thickener content, and the effect was more significant when the thickener content changed from 0.6% to 0.8%. Under different thickener addition amounts, fresh acid mainly improved the core permeability. After core-flooding, micropores and mesopores (51.26–632.15 μm) were dissolved and enlarged, forming mesopores and macropores (632.15–3597.73 μm); when the thickener content increased to 0.8%, the solubility of acid decreased, and the pore volume increment and maximum pore size both decreased. On the other hand, residual acid mainly damages the core, thickener molecules in the acid occupying mesopore, leading to an overall shift in pore distribution from mesopores (145.24–335.53 μm) to micropores (20.59–126.32 μm), with the thickener content increased to 0.8%, the damage volume of mesopore increased by 723.90%. Based on the research results, the reduced thickener content was initially applied to the West Sichuan gas field, achieving a better acidizing effect.

IOT Based Portable Fire Extinguisher using Acoustic Setup

Despite their effectiveness, conventional fire extinguishers come with notable drawbacks such as chemical residue and environmental damage. Addressing these concerns, recent research proposes a revolutionary solution: utilizing sound waves to combat fires. This innovative approach introduces a portable extinguisher device designed to efficiently diminish flame energy and extinguish fires by concentrating sound waves through a vortex cannon. Extensive testing across various fuel types, including gas, liquid, and solid, has demonstrated the effectiveness of this technology. Findings indicate that the optimal frequency range for extinguishment is around 60 Hz. These results underscore the capability of this novel method to swiftly extinguish fires of diverse origins. Moreover, beyond its efficacy in extinguishing flames, this technology holds the potential to significantly reduce property loss and human casualties by enabling early-stage fire intervention. By leveraging this strategy, fire safety procedures could undergo a transformative shift, offering a more sustainable, safer, and cleaner solution by mitigating the drawbacks associated with traditional fire extinguishers and introducing a versatile approach applicable across different fuel types, this advancement represents a significant step forward in fire safety technology. Its adoption could lead to profound improvements in fire fighting practices, enhancing both environmental sustainability and public safety.

A novel nonlinear fatigue cumulative damage model based on machine learning

Machine learning serves as a potent tool for predicting fatigue damage. By integrating traditional physics-based models with machine learning techniques, prediction accuracy can be notably enhanced. Drawing from a substantial pool of experimental data, this article introduces a novel nonlinear fatigue cumulative damage model. This model combines the traditional Manson-Halford model with machine learning algorithms, enabling the prediction of residual fatigue damage across various materials. The predictive capabilities of this model are compared with those of traditional approaches. The article subsequently investigates the key parameters influencing the nonlinear fatigue cumulative damage model. The findings demonstrate that the proposed model exhibits significantly higher accuracy in residual fatigue damage prediction compared to traditional methods. Notably, the primary factor impacting the nonlinear cumulative fatigue damage model is identified as the first level loading damage. This study underscores the substantial potential of the proposed nonlinear fatigue cumulative damage model for predicting residual fatigue damage.