Critical Damages Research Articles

The Anti-Flyaway/Frizz Effect by Inducing the α-Helical Structure Transition of Hair

In order to reduce chronic hair flyaways/frizz, both reducing and oxidizing agents have to be used, leaving aside the hair damage issues. This study presents changes in hair morphology caused by treatment with a shampoo containing only reducing agents, excluding oxidizing agents that affect critical hair damages. As a result of flyaway/frizz improvement rates calculated through monitoring of the area of light transmittance in the hair tresses, reducing agents, such as ammonium thioglycolate (ATG), L-cysteine, and sodium sulfite were found to be effective in decreasing hair flyaway/frizz. Additionally, the methods to maintain homeostasis and control damage caused by oxidation during washing were also used to see flyaway/frizz improvement rates. Measurements using electrostatic force microscopy (EFM) showed that the surface charge of hair tresses treated with shampoo containing reducing agents was lowered. Using Raman spectroscopic analysis, it has been suggested that these treatments with reducing agents induced a 3D structural transition of the hair from an α-helix to a random coil. In addition, this structural release was confirmed, identifying the reduction in the enthalpy of the α-helix using differential scanning calorimetry (DSC). Furthermore, we verified that this change causes no hair damage through a tensile strength test. Therefore, the formulation of shampoo with reducing agents can be used as an effective strategy to care for hair flyaway/frizz without hair damage issues.

Advanced Methods for Monitoring and Fault Diagnosis of Control Loops in Common Rail Systems

Common rail systems are a key component of modern diesel engines and highly increase their performance. During their working lifetime, there could be critical damages or failures related to aging, like backlash or friction, or out-of-spec operating conditions, like low-quality fuel with, e.g., the presence of water or particles or a high percentage of biodiesel. In this work, suitable data-driven methods are adopted to develop an automatic procedure to monitor, diagnose, and estimate some types of faults in common rail systems. In particular, the pressure control loop operating within the engine control unit is investigated; the system is described using a Hammerstein model composed of a nonlinear model for the control valve behavior and an extended linear model for the process dynamics, which also accounts for the presence of external disturbances. Three different sources of oscillations can be successfully detected and quantified: valve stiction, aggressive controller tuning, and external disturbance. Selected case studies are used to demonstrate the effectiveness of the developed methodology.

Sustainable quaternary binders made from metallurgical wastes of northeast Mexico: strength, hydration products, and durability.

In this research, four industrial wastes were used for up to 80% as supplementary cementitious materials (SCMs) in cement mortar systems: ground granulated blast furnace slag, electric arc furnace slag, basic oxygen furnace slag, and waste limestone powder. Quaternary cementitious blends were prepared and studied for up to 120days. Workability, compressive strength, durability, microstructures, and sustainability studies were performed and compared with Portland cement references. Results showed that more than 30MPa in compressive strength can be achieved by > 50% replacement with SCMs; only 9% below the reference. Neither H2SO4 nor MgSO4 attacks resulted in critical damages; nevertheless, curing under NaCl solution showed detrimental behavior. C-S-H with a low Ca/Si ratio was identified in the mortars as the main hydration product, possibly intermixed with stratlingite, C-A-S-H and/or hydrotalcite. Environmental impact for the blended cements was determined as the CO2eq. factor from a simple life cycle assessment. The embodied greenhouse gasses varied in 260.2-541.4kg CO2eq./ton of binder depending on the formulation. This was 40-70% less than Portland cement (922.6kg CO2eq./ton). The production of the raw materials dominated the polluting emissions, while freight, grinding, and sieving had little environmental impact.

Structural Health Monitoring on Road Bridge: Application Cases of Optical Strand Sensor in JAPAN

In Japan, many of the major civil infrastructures such as road bridges, railways and tunnels was built during our high-growth period from the mid-1950s to the early 1970s. The number of these structures that has been more than 50 years old after construction, has been rapidly increasing in recent years. In this context, expectations for Structural Health Monitoring (SHM) have been rising to optimize its management and maintenance to extend its lifespan and ensure the safety of users. Although a variety of IoT sensors are developing and their precision is improving day by day, SHM still has crucial challenges, e.g., if it can really identify critical damages to structures, determine quantitative assessment of the serviceability limit, evaluate the safety of a structure quickly after major events such as earthquakes, or so on. In order to achieve our original goals, it is essential to accumulate practical applications of SHM by dedicating a specific sensor solution to a specific issue. The authors have introduced a unique and competitive Optical Strand Technology developed by OSMOS Groupe in France and have been providing the service of SHM mainly on civil infrastructures for more than 20 years in Japan. This paper presents some application cases of SHM to road bridges by means of Optical Strand Sensor which provide for different types of purposes and future prospects.

A novel two-scale nonlinear damage accumulation model for vibration fatigue life prediction

Vibration is the main factor causing high cycle fatigue. The macro-response stress and strain of the structure under the excitation of vibration load are generally in the elastic stage. However, fatigue failure still occurs due to long-term cyclic load, which is unexplainable by the macro-plastic accumulation method. Therefore, a two-scale nonlinear damage accumulation model is proposed for vibration fatigue based on the physical characteristics of multi-scale fatigue damage evolution. In this model, two-scale elastic-plastic constitutive equations based on the equivalent inclusion theory are built, and a two-stage damage accumulation strategy with two critical damages is designed. A resonance fatigue life prediction algorithm is established based on the proposed model, and a validation test is carried out using the cantilever beam made of GH4169 alloy. The results show that the deviation between the vibration fatigue life prediction and test results is within a scatter band of factor 2, indicating that the two-scale nonlinear damage accumulation model is effective in the vibration fatigue region.

The effect of the gravity on the earthquake performance of roller compacted concrete dams

Roller compacted concrete (RCC) is a dry concrete mixture often utilized in the construction of large dams. The interlayer of the RCC dam, which is the weakest plane of the structure, can easily fail under hydraulic shear load, geological impact, earthquake force and environmental impact. In this study linear and performance analyzes were carried out for eight different scenarios for foundation effect, gravity effect and empty and full reservoir situations. In analyses, the earthquake response and performance of the Akçakoca RCC Dam, taking into account the interaction between the dam and the water. The reservoir water behavior is simulated using the Eulerian-Lagrangian coupled (CEL) approach with finite elements modeling. Linear analyses reveal that hydrodynamic pressure leads to increased displacements and principal stresses. The earthquake performance evaluation of the Akçakoca RCC dam indicates that critical concrete damages are expected based on linear time-history analyses conducted for both empty and full reservoir scenarios. Besides, according to this study, gravity effect clearly increases the earthquake performance of the dam.

Time to capsize for damaged passenger ships in adverse weather conditions. A Multi-modal analysis

After an accident in open seas, the final fate for a damaged ship could be the loss of stability/floatability and consequently capsize/sinkage. The latter may occur even in calm water, but is more critical and probable in adverse weather conditions, i.e., in irregular waves. Identifying a possible capsize event and determining the time that it takes for the ship to capsize is extremely important for safety and risk assessment, meaning whether it would be possible or not to evacuate the ship in a specific scenario and the possibility of loss of life. In this respect, and notwithstanding the impact of many other factors, model tests or time-domain simulations could be used to provide answers to this question. However, even in this case, dealing with irregular waves, entails that both approaches are affected by the random nature of phase spectral components, which leads to a different time to capsize determination at each run/simulation or to the identification of cases where the vessel is not capsizing in the given time window. Here, a dedicated study is provided to describe the time to capsize in irregular waves for critical damages. Simulations performed on a passenger ship at different wave heights and different metacentric heights highlights the appearance of more than one capsize mode for the same damage case. A model based on Mixed-Weibull distributions has been developed to describe the multi-modal behaviour of the time to capsize distributions for the analysed damage cases.

Effects of diabetes-induced hyperglycemia on epigenetic modifications and DNA packaging and methylation during spermatogenesis; A narrative review.

The impact of diabetes on various organs failure including testis has been highlighted during the last decades. If on one hand diabetes-induced hyperglycemia has a key role in induced damages; on the other hand, glucose deprivation plays a key role in inducing male infertility. Indeed, glucose metabolism during spermatogenesis has been highlighted due to post-meiotic germ cells drastic dependence on glucose-derived metabolites, especially lactate. In fact, hyperglycemia-induced spermatogenesis arrest has been demonstrated in various studies. Moreover, various sperm maturation processes related to sperm function such as motility are directly depending on glucose metabolism in Sertoli cells. It has been demonstrated that diabetes-induced hyperglycemia adversely impacts sperm morphology, motility and DNA integrity, leading to infertility. However, fertility quality is another important factor to be considered. Diabetes-induced hyperglycemia is not only impacting sperm functions, but also affecting sperm epigenome. DNA packing process and epigenetics modifications occur during spermatogenesis process, determining next generation genetic quality transmitted through sperm. Critical damages may occur due to under- or downregulation of key proteins during spermatogenesis. Consequently, unpacked DNA is more exposed to oxidative stress, leading to intensive DNA damages. Moreover, epigenetic dysregulation occurred during spermatogenesis may impact embryo quality and be transmitted to next generations, increasing offspring genetic issues. Herein we discuss the mechanisms by which diabetes-induced hyperglycemia can affect epigenetic modifications and DNA packaging and methylation during spermatogenesis thus promoting long-lasting effects to the next generation.

On the ductile damage progression in surface-damaged metallic strands: Towards a damage tolerance analysis

This paper reports a novel and straightforward numerical approach to perform a damage tolerance analysis for metallic strands. This methodology relies on the ductile damage evolution laws experienced by metallic wires and strands under tensile monotonic load. Regarding the wires, this new approach integrates both micromechanics–based and continuum damage mechanics-based approaches. Tensile capacity tests of high strength steel and aluminium alloy wires are simulated using 3-D nonlinear finite element models along with the Gurson-Tvegaard-Needleman constitutive plasticity-damage model (micromechanics–based approach) whose parameters are calibrated iteratively using the disturbed state concept. Numerical simulations reproduce the different phases of the ductile damage process which are then related to an isotropic damage index (continuum damage mechanics-based approach). Results show that the wires develop nonlinear ductile damage evolution laws well captured by the Bonorás model with critical damages ranging from 0.12 to 0.25. The existing gap between wires and strand damage evolutions is then filled by using proper kinematic assumptions for both intact and damaged strands along with a homogenization procedure. The latter have a prescribed number of surface wires, symmetrically and asymmetrically distributed, fully cut to simulate service damage. For validation purposes, strands with 1 × 7 construction typology are analyzed whose diameters range between [9.5–14.3] mm. One approach to assess strands structural integrity and safety conditions is to analyze the stability of damage states as the degradation process occurs. Using this metric for the 1 × 7 strands, reveals that two surface wires cut is the maximum acceptable surface damage which meets the criterion established in different international standards for this strand construction typology. Otherwise, the damage state progresses to either an unstable or inflection state that accelerates the reduction of the capacity of a damaged strand to withstand more damage.

In-situ quantitative tracking of micro-crack evolution behavior inside CMCs under load at high temperature: A deep learning method

Micro-cracks play an extremely significant role in the failure of ceramic matrix composites (CMCs). In-situ quantitative tracking of micro-crack evolution behavior remains a great challenge. In this study, a deep learning micro-crack segmentation method based on the generative adversarial network was developed to quantitatively characterize the micro-crack evolution behavior of CMCs under tensile load at high temperature with in-situ X-ray computed micro-tomography (μCT). This method realizes a precise and robust segmentation of the micro-cracks in μCT images with low gray contrast and image quality caused by noise and artifacts. The crack parameters including crack opening area, crack opening displacement and crack volume of each micro-crack were obtained. For the most micro-cracks, the values of these parameters exhibited no obvious increase during the loading process. Noticeable increasing of crack parameters occurred in some large micro-cracks at high load levels. The evolution of each micro-crack was also tracked to further identify the critical damages dominating the eventual failure. The four largest cracks exhibiting a more dramatic volume evolution were captured as the main cracks. These main cracks all originated from the preexisting micro-cracks and were usually formed by the coalescence of adjacent small micro-cracks with increasing tensile loads. The ultimate fracture was demonstrated to take place near these main cracks.

The effect of the operational environment on the survivability of passenger ships

The in-force probabilistic framework for passenger ship survivability assessment covers collision hazards. The framework primarily pertains to a static approach. Nonetheless, more complex dynamic analyses usually employ the same damage definitions, adding besides the breach characteristics, the environmental condition selection or, more precisely, the irregular wave environment necessary to simulate the damage scenarios. The traditional dynamic approaches to survivability consider only the significant wave height sampled from statistical formulations, with the wave period deriving from a constant steepness assumption. However, wave height and period influence ship dynamics in waves differently, especially concerning survivability after damage. Therefore, aiming at a direct assessment of ship survivability and the probability of loss of lives determination in realistic operational scenarios, it is essential to properly study the influence of combined variations of wave height and periods and their occurrence. The present study proposes a methodology for dynamic simulations in site-specific conditions derived from the Global Wave Statistics. The study documents the process in two critical collision damages for a reference passenger ship, using wave height and period combinations typical of the main sea areas of interest for passenger ships and performing a sensitivity analysis on the simulations needed to evaluate survivability. This enhanced analysis allows identifying the limiting environmental conditions for the critical damage cases, including the effect of heading variations, determining the ship’s survivability to specific damage in an operational area.

REMOTE SENSING FOR FLOOD INUNDATION MAPPING USING VARIOUS PROCESSING METHODS WITH SENTINEL-1 AND SENTINEL-2

Abstract. The following paper discusses different remote sensing methodologies for flood mapping. The chosen study area is nearby Karlovo, Bulgaria where torrential rains in August and September 2022 caused devastating damages in the area. The location is still under critical status and damages are not completely evaluated, yet.The aim of this study is to investigate how open satellite data can be applied in the mapping the results from the floods. The research team worked with radar and optical data from Sentinel-1 and Sentinel-2. Different technological approaches were applied to classify the land cover changes. Given the fact that the flood mass consisted mainly of mud an innovative approach was considered in order for the damages area to be computed.Climate change predictions and deforestation suggest increasingly frequent floods in the future. For these reasons, rapid and timely flood mapping under specific conditions is very important in flood modelling, hazard and risk analysis. In order to investigate the flooded area in the region of the selected study area, different post-processing methods were used. The research team focused on using satellite imagery from both Sentinel-1 and Sentinel-2. Various spectral indices were computed as well as unsupervised and supervised classifications were applied. The results of the study were presented in the form of statistical analyses and comparison between the computational methods.

Therapeutic effect of gossypetin against paraquat-induced testicular damage in male rats: a histological and biochemical study.

Paraquat (PQ) is an organic compound, which is commonly used as a herbicide in the agriculture sector, and it is also known to stimulate critical damages in the male reproductive system. Gossypetin (GPTN) is one of important members of the flavonoid family, which is an essential compound in flowers and calyx ofHibiscus sabdariffawithpotential pharmacological properties. The current investigation was aimed to examine the ameliorative potential of GPTN against PQ-instigated testicular damages. Adult male Sprague-Dawley rats (n = 48) were distributed into four groups: control, PQ (5mg/kg), PQ + GPTN (5mg/kg + 30mg/kg respectively), and GPTN (30mg/kg). After 56days of treatment, biochemical, spermatogenic indices, hormonal, steroidogenic, pro-or-anti-apoptotic, and histopathological parameters were estimated. PQ exposure disturbed the biochemical profile by reducing the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GSR), while it increased the concentration of reactive oxygen species (ROS) and malondialdehyde (MDA) level. Furthermore, PQ exposure decreased the sperm motility, viability, number of hypo-osmotic tail swelled spermatozoa, and epididymal sperm count; additionally, it increased sperm morphological (head mid-piece and tail) abnormalities. Moreover, PQ lessened the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and plasma testosterone levels. Besides, PQ-intoxication downregulated the gene expression of steroidogenic enzymes (StAR, 3β-HSD, and 17β-HSD) and anti-apoptotic marker (Bcl-2), whereas upregulated the gene expression of apoptotic markers (Bax and Caspase-3). PQ exposure led to histopathological damages in testicular tissues as well. Nonetheless, GPTN inverted all the illustrated impairments in testes. Taken together, GPTN could potently ameliorate PQ-induced reproductive dysfunctions due to its antioxidant, androgenic, and anti-apoptotic potential.

A stochastic framework for computationally efficient fail-safe topology optimization

Fail-safe robustness is an important design philosophy for critical structural systems such as airframes. The basic idea of fail-safe design is that a structure should be designed to survive normal loading conditions when local damage occurs. In the context of topology optimization, fail-safe consideration innovates the morphogenesis for structural design in addition to the parametric safety margin. Existing fail-safe topology optimization methods usually enumerate all/predefined possible damages among the design domain and optimize the worst-damage scenario. However, virtually all damages can occur and cause the structural system to stop functioning. This work proposes the Stochastic Fail-Safe Topology Optimization (S-FSTO) for computationally viable fail-safe topology optimization which considers all possible damages according to the associated severity, including the worst-damage scenario. Critical damages for density value updates are sampled through the proposed two-level sampling strategy, which allows arbitrary size and location of damages. A design domain segmentation strategy is proposed to improve the sampling efficiency. The required number of FEA runs could be reduced by multiple orders of magnitudes. The proposed S-FSTO could be conveniently equivalent to a variety of existing schemes by customizing the proposal distributions of the two-level sampling strategy. The dependence on subjective decisions for selecting local damages could be minimized. The proposed framework has been evaluated for the design of cantilever beams and airplane bearing brackets. The generated conceptual designs are significantly more robust than the deterministic ones when local damage occurs. For the design of cantilever beams, S-FSTO produced designs with similar performance as that from the original FSTO and saved 99.4% FEA runs.

Soil–Structure Interaction Effect on the Resistance of a Steel Frame against Progressive Collapse Using Linear Static and Nonlinear Dynamic Procedures

In recent years, increases in terrorist attacks or other unexpected explosions have shown that their effects can cause critical damages to buildings and cause partial or total collapse of buildings. This chain collapse mechanism is named a progressive collapse. Subsoil effects on a building are often ignored in studies on progressive collapse. In this study, the effect of soil–structure interaction on the risk of progressive collapse of a steel frame is investigated by using the modified Vlasov model, which has not been used in the studies on progressive collapse before. For this purpose, a steel building model was investigated. A linear static procedure (LSP) and nonlinear dynamic procedure (NDP) with alternative path method were used for the analysis of the frame. SAP2000 software was used to model subsoil effect on the frame via an interface coded in MATLAB interactively. The results from the analyses showed that the soil–structure interaction effect can significantly affect the progressive collapse resistance of the building.

A Modified Full-Scale Experimental Method on the Seismic Performance of Complex Façade System

ABSTRACT The façade system is one type of building envelope. It is both acceleration sensitive and displacement sensitive under dynamic loads. However, some novel complex façade systems lack comprehensive study, especially under earthquake excitations, and full-scale shaking table test for both façade system with the main structure is expensive. Thus, a test design procedure is proposed, which includes the input excitations into the façade by using the finite element method (FEM) model, and aims for achieving acceleration and drift demands for acceleration-and-displacement sensitive nonstructural components (NCs). According to this procedure, full-scale shaking table tests for the façade system only are designed and conducted under different earthquake intensity levels. The responses (such as acceleration and displacement) are recorded, and critical damages (such as the relative residual displacement between panels and bolt scratch) are observed. Several key factors that affect the seismic performance, such as the component acceleration amplification factor and the required distance to prevent collision between panels, are discussed.

The Relationship between Reactive Oxygen Species and the cGAS/STING Signaling Pathway in the Inflammaging Process

During Inflammaging, a dysregulation of the immune cell functions is generated, and these cells acquire a senescent phenotype with an increase in pro-inflammatory cytokines and ROS. This increase in pro-inflammatory molecules contributes to the chronic inflammation and oxidative damage of biomolecules, classically observed in the Inflammaging process. One of the most critical oxidative damages is generated to the host DNA. Damaged DNA is located out of the natural compartments, such as the nucleus and mitochondria, and is present in the cell's cytoplasm. This DNA localization activates some DNA sensors, such as the cGAS/STING signaling pathway, that induce transcriptional factors involved in increasing inflammatory molecules. Some of the targets of this signaling pathway are the SASPs. SASPs are secreted pro-inflammatory molecules characteristic of the senescent cells and inducers of ROS production. It has been suggested that oxidative damage to nuclear and mitochondrial DNA generates activation of the cGAS/STING pathway, increasing ROS levels induced by SASPs. These additional ROS increase oxidative DNA damage, causing a loop during the Inflammaging. However, the relationship between the cGAS/STING pathway and the increase in ROS during Inflammaging has not been clarified. This review attempt to describe the potential connection between the cGAS/STING pathway and ROS during the Inflammaging process, based on the current literature, as a contribution to the knowledge of the molecular mechanisms that occur and contribute to the development of the considered adaptative Inflammaging process during aging.

A Novel Pentagonal EC Sensing Array Film for Quantifying Hole-Edge Crack of Bolted Joints

Hole-edge crack in bolted joints is one of the most critical damages that seriously affect aircraft structural safety. In this article, a novel pentagonal eddy current (EC) sensing array film is proposed to quantify the hole-edge crack parameters. The proposed new sensing film may identify the hole-edge crack angle, depth, and length with fewer layers and eliminate the blind area problem of crack monitoring for the existing sensors at some angles. Finite-element simulation is employed to study the EC distribution around the bolt hole and the interaction between the EC and the crack, which can be used to determine the configuration of the EC array. Both the simulation and the experimental test are conducted to verify the feasibility and effectiveness of the proposed sensing film for quantifying the hole-edge crack angle, depth, and length.

Numerical study of the effect of Post-Liquefaction settlements on the response of infilled RC-frames

The liquefaction of soils is one of the most severe results of earthquakes. Indeed, post-liquefaction settlements are the main responsible for critical damages and collapse in shallow-founded buildings. The study of the behavior of buildings subjected to post-liquefaction settlements is rather complex since it requires to consider the interaction between the effects of ground shaking and the effects of liquefaction failure. In particular, large inelastic deformations occurring during severe earthquakes are responsible for residual permanent displacements which could particularly influence the response of structures with respect to post-liquefaction settlements. In this paper it is presented a simplified numerical approach finalized to assess the response of infilled reinforced concrete (RC) frames toward post-liquefaction settlements. Like to a previous approach presented by the Authors for bare RC-frames, the proposed approach is based on a procedure where the influence of seismic inelastic displacements on the effect of post-liquefaction settlements is evaluated throughout a set of static nonlinear analyses instead of more complex dynamic time-history analyses. Here, in addition, the Authors opportunely enrich the approach to account for the influence of the damage attained by the infill on both the seismic response and post-liquefaction settlements. After a preliminary discussion concerning some important aspects of the behavior of infilled RC-frames toward seismic events and post-liquefaction settlements, the proposed approach is presented in detail and applied to some cases of study deduced from literature. Additional numerical analyses are also performed in order to further underline the ability of the approach to account for the important role of infill panels on the seismic response and the subsequent activation of post-liquefaction settlements.

Critical damages identification in a multi-level damage stability assessment framework for passenger ships

The damaged stability assessment for a passenger ship is a process requiring the simulation of multiple damage scenarios. Nevertheless, the stochastic nature of the damage stability framework requires the analysis of a statistically significant number of cases. On the other hand, the probability density functions used to estimate the possible damage dimensions and locations along the ship generate many scenarios that are not critical for the ship’s survivability, especially for large passenger ships. It is standard to apply empirical rules to restrict the number of damage scenarios, such as critical damages is only above two compartments, considering that damage stability regulations currently in force ensure survivability levels beyond this extent of breaches. However, a rigorous approach is lacking. To this end, in the present work, it is proposed to use more scientific-based methods to identify critical damages. This paper presents three original approaches developed in the context of a multi-level damage stability assessment. The first method relies on preliminary static calculations, the second on the energy absorbed by the ship during an impact, and the third on a purely dynamic approach. Here, the methods are critically compared on two sample passenger ships for collision damages, showing their respective advantages and disadvantages.