In the last decades, the applications of structural monitoring are moving toward the field of civil engineering and infrastructures. Nevertheless, if the structures have damages, it does not mean ...that they have a complete loss of functionality, but rather that the system is no longer in an optimal condition so that, if the damage increases, the structure can collapse. Structural Health Monitoring (SHM), a process for the identification of damage, periodically collects data from suitable sensors that allow to characterize the damage and establishes the health status of the structure. Therefore, this monitoring will provide information on the structure condition, mostly about its integrity, in a short time, and, for infrastructures and civil structures, it is necessary to assess performance and health status. The aim of this work is to design an Internet of Things (IoT) system for Structural Health Monitoring to find possible damages and to see how the structure behaves over time. For this purpose, a customized datalogger and nodes have been designed. The datalogger is able to acquire the data coming from the nodes through RS485 communication and synchronize acquisitions. Furthermore, it has an internal memory to allow for the post-processing of the collected data. The nodes are composed of a digital triaxial accelerometer, a general-purpose microcontroller, and an external memory for storage measures. The microcontroller communicates with an accelerometer, acquires values, and then saves them in the memory. The system has been characterized and the damage indicator has been evaluated on a testing structure. Experimental results show that the estimated damage indicator increases when the structure is perturbed. In the present work, the damage indicator increased by a maximum value of 24.65 when the structure is perturbed by a 2.5 mm engraving.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Continuum damage mechanics (CDM) has sparked a lot of scientific attention during the last few decades. The CDM approach defines a damage variable as an effective surface density of microcracks or ...voids with a plane of representative volume element to circumvent the scale mismatches in the involved physics. The smallest volume element at which a solid is regarded as continuous and all of the material's properties are represented as homogenized variables is referred as the representative volume element. A vital and challenging issue in CDM is to quantify the damage variable D. The various direct and indirect techniques of damage appraisal methodologies are extensively discussed in this review. The direct method is qualitative, whereas the indirect method is quantitative. Damage assessment using an indirect approach is simple and can be obtained through experiments. The evaluation of damage by degradation of elasticity modulus, an indirect method, has proven to be more popular and accurate than the other methods for ductile materials. The present work reviews and summarizes the various ductile damage development models, their evolution through time, and the importance of CDM in contemporary engineering research.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The problem of characterizing the structural residual life is one of the most challenging issues of the damage tolerance concept currently applied in modern aviation. Considering the complexity of ...the internal architecture of composite structures widely applied for aircraft components nowadays, as well as the additional complexity related to the appearance of barely visible impact damage, prediction of the structural residual life is a demanding task. In this paper, the authors proposed a method based on detection of structural damage after low-velocity impact loading and its classification with respect to types of acting stress on constituents of composite structures using the developed processing algorithm based on segmentation of 3D X-ray computed tomograms using the
package, real-oriented dual-tree wavelet transform and supporting image processing procedures. The presented algorithm allowed for accurate distinguishing of defined types of damage from X-ray computed tomograms with strong robustness to noise and measurement artifacts. The processing was performed on experimental data obtained from X-ray computed tomography of a composite structure with barely visible impact damage, which allowed better understanding of fracture mechanisms in such conditions. The gained knowledge will allow for a more accurate simulation of structural damage in composite structures, which will provide higher accuracy in predicting structural residual life.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Wind damage is one of the major factors affecting forest ecosystem sustainability, especially in the coastal region. Typhoon Lekima is among the top five most devastating typhoons in China and caused ...economic losses totaling over USD 8 billion in Zhejiang Province alone during 9–12 August 2019. However, there still is no assessment of its impacts on forests. Here we detected forest damage and its spatial distribution caused by Typhoon Lekima by classifying Landsat 8 OLI images using the random forest (RF) machine learning algorithm and the univariate image differencing (UID) method on the Google Earth Engine (GEE) platform. The accuracy assessment indicated a high overall accuracy (>87%) and kappa coefficient (>0.75) for forest-damage detection, as evaluated against field-investigated plot data, with better performance using the RF method. The total affected forest area by Lekima was 4598.87 km2, accounting for 8.44% of the total forest area in Zhejiang Province. The light-, moderate- and severe-damage forest areas were 2106.29 km2, 2024.26 km2 and 469.76 km2, respectively. Considering the damage severity, the net forest canopy loss fraction was 2.57%. The affected forest area and damage severity exhibited large spatial variations, which were affected by elevation, slope, precipitation and forest type. Our study indicated a larger uncertainty for affected forest area and a smaller uncertainty for the proportion of damage severity, based on multiple assessment approaches. This is among the first studies on forest damage due to typhoons at a regional scale in China, and the methods can be extended to examine the impacts of other super-strong typhoons on forests. Our study results on damage severity, spatial distribution and controlling factors could help local governments, the forest sector and forest landowners make decision on tree-planting planning and sustainable management after typhoon strikes and could also raise public and governmental awareness of typhoons’ damage on China’s inland forests.
Acute treatment with replication-stalling chemotherapeutics causes reversal of replication forks. BRCA proteins protect reversed forks from nucleolytic degradation, and their loss leads to ...chemosensitivity. Here, we show that fork degradation is no longer detectable in BRCA1-deficient cancer cells exposed to multiple cisplatin doses, mimicking a clinical treatment regimen. This effect depends on increased expression and chromatin loading of PRIMPOL and is regulated by ATR activity. Electron microscopy and single-molecule DNA fiber analyses reveal that PRIMPOL rescues fork degradation by reinitiating DNA synthesis past DNA lesions. PRIMPOL repriming leads to accumulation of ssDNA gaps while suppressing fork reversal. We propose that cells adapt to repeated cisplatin doses by activating PRIMPOL repriming under conditions that would otherwise promote pathological reversed fork degradation. This effect is generalizable to other conditions of impaired fork reversal (e.g., SMARCAL1 loss or PARP inhibition) and suggests a new strategy to modulate cisplatin chemosensitivity by targeting the PRIMPOL pathway.
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•Multiple cisplatin doses suppress reversed fork degradation in BRCA-deficient cells•The PRIMPOL adaptive response suppresses fork reversal and leads to ssDNA gaps•The ATR kinase regulates the PRIMPOL-mediated adaptive response•Impaired fork reversal shifts the balance toward PRIMPOL-mediated repriming
Reversed replication forks are degraded in BRCA-deficient cells. Quinet et al. show that treatment with multiple cisplatin doses promotes PRIMPOL repriming while suppressing fork reversal and preventing degradation. These studies identify a new function of PRIMPOL in the replication stress response and explain how cells adapt to multiple drug doses.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The manuscript has been revised carefully according to the comments and advices of the reviewers.•An efficient method for the simulation on fatigue behavior of reinforced concrete structures is ...proposed.•Fatigue damage accumulation for both concrete and reinforcement are considered and modeled.•An expediting calculation technique for fatigue simulation is developed.•High efficiency fatigue simulations on reinforced concrete structure are performed.
This paper mainly focuses on developing an efficient simulation method for fatigue behavior of reinforced concrete structures (RC structures), through which the damage state and the potential fatigue damage failure pattern of the RC structures could be obtained in finite element analysis (FEA). In order to accomplish such object, fatigue behavior of RC structures is studied using the entire history of damage accumulation for both concrete and steel bars. A bi-scalar damage-plasticity constitutive model for concrete and a single-scalar damage constitutive model for reinforcement are first introduced to characterize the fatigue damage state of the structure. Then, a two-scale temporal expediting computational technique is developed for the material constitutive models, by which the original material models could be split into a micro periodic time scale portion and a macro homogenized time scale portion. Through this calculation technique, the original increment-by-increment FEA procedures could be transferred to the two-time scale calculation, which would greatly enhance the efficiency of the structural fatigue simulation. By combining the material constitutive models and the expediting calculation technique with FEA, a set of numerical examples and comparisons are performed, specifically, a column-drilled shaft connection in bridge structure is simulated, which validates the effectiveness and reliability of the current simulation method for the fatigue behavior of RC structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This research explores the utilization of the Black Marble nighttime light (NTL) product to detect and assess damage caused by hurricanes, tornadoes, and earthquakes. The study first examines average ...regional NTL trends before and after each disaster, demonstrating that NTL patterns for hurricanes closely align with the features of a resilience curve, unlike those for earthquakes and tornadoes. The relative NTL change ratio is computed using monthly and daily NTL data, effectively reducing variance due to daily fluctuations. Results indicate the robustness of the NTL change ratio in detecting hurricane damage, whereas its performance in earthquake and tornado assessment was inconsistent and inadequate. Furthermore, NTL demonstrates a high performance in identifying hurricane damage in well-lit areas and the potential to detect damage along tornado paths. However, a low correlation between the NTL change ratio and the degree of damage highlights the method’s limitation in quantifying damage. Overall, the study offers a promising, prompt approach for detecting damaged/undamaged areas, with specific relevance to hurricane reconnaissance, and points to avenues for further refinement and investigation.
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According to the Intergovernmental Panel on Climate Change (IPCC) Reports, climate variability and changes increase the possibility of extreme weather events causing climate-related hazards and the ...risk of natural disasters. A storm is one of the most common and serious natural hazards that pose significant human and economic damage costs worldwide. The Korean Peninsula is also at persistent risk of hydro-meteorological disasters induced by rainstorms and typhoons due to geomorphological features and climate change impacts. This study has, therefore, proposed the damage vulnerability index for a spatial assessment of the damage vulnerability to storms, based on the IPCC’s vulnerability assessment concept. The damage vulnerability index is aggregated from the potential indicator for the potential damage targets, estimated by the population and major facility densities, and the risk indicator for the expected damage risk, estimated by the risk analysis for integrating both frequency and severity of human and economic damage cost records. The damage vulnerability index can assess regions vulnerable to the disaster damage induced by rainstorms, typhoons, and both, respectively, over the 231 administrative districts in the Republic of Korea. It is expected that the proposed damage vulnerability index can provide realistic and practical information on sustainable damage mitigation plans for the nationwide administrative districts against storm-induced disasters.
DNA damage is the dominant source of mutation, which is the driving force of evolution. Therefore, it is important to quantitatively analyze the DNA damage caused by different mutagenesis methods, ...the subsequent mutation rates, and their relationship. Atmospheric and room temperature plasma (ARTP) mutagenesis has been used for the mutation breeding of more than 40 microorganisms. However, ARTP mutagenesis has not been quantitatively compared with conventional mutation methods. In this study, the umu test using a flow-cytometric analysis was developed to quantify the DNA damage in individual viable cells using Salmonella typhimurium NM2009 as the model strain and to determine the mutation rate. The newly developed method was used to evaluate four different mutagenesis systems: a new ARTP tool, ultraviolet radiation, 4-nitroquinoline-1-oxide (4-NQO), and N-methyl-N’-nitro-N-nitrosoguanidine (MNNG) mutagenesis. The mutation rate was proportional to the corresponding SOS response induced by DNA damage. ARTP caused greater DNA damage to individual living cells than the other conventional mutagenesis methods, and the mutation rate was also higher. By quantitatively comparing the DNA damage and consequent mutation rate after different types of mutagenesis, we have shown that ARTP is a potentially powerful mutagenesis tool with which to improve the characteristics of microbial cell factories.
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CEKLJ, DOBA, EMUNI, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Several isotropic creep damage models and corresponding microstructure damage mechanisms are described in detail.•Some anisotropic creep damage models and the physical meaning of the anisotropic ...damage tensor are discussed in detail.•Material constants in creep damage models for materials of different engineering components operated at high temperature are shown.•Applications of creep damage models for crack growth analysis in pipes are given.
Important advances in creep damage models for crack growth analysis have been made in the last two decades as scientists and engineers strive to imbue continuum-based models with more realistic details at microstructure damage mechanisms in the creep process. Such damage models are reviewed with the aim of providing users insight into the key ideas, features and differences of prevailing models in this paper. Several isotropic damage models and corresponding microstructure damage mechanisms are described. Furthermore, some anisotropic damage models and the physical meaning of the anisotropic damage tensor are discussed. Some applications for these models are also given.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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