Main Damage Research Articles

Dual-purpose nanoparticle assembly for identifying preferential intracellular targets of oxindolimine copper(II) complexes through SERS imaging

In this study, the main goal was to identify the intracellular targets of oxindolimine copper(II) complexes by SERS and Raman imaging of living HeLa cells, whose action as a cancer inhibitor has been previously determined. The used SERS probe was constituted of spherical gold nanoparticles together with the Raman reporter 5,5′-dithiobis-2-nitrobenzoic acid (DTNB) and oxindolimine copper(II) complexes, [Cu(isatp)Cl] and [Cu(nisatp)H2O]. Two excitation radiations were used to acquire living single HeLa cells images: 532 nm to acquire the conventional Raman information of the cells and 785 nm to acquire the localization of the modified SERS probe inside the cells. The Raman images of the main intracellular components were obtained by multivariate analysis, and the SERS images were obtained by univariate analysis using a Raman reporter. The SERS and Raman images showed that the complexes could enter the cells together with the gold nanoparticles, causing main damage to the nuclei and lipids-rich region. In addition, there was no evidence of water entry into the cell.

Seismic fragility analysis of rocking buckling-resistant braced structures subjected to far-field and near-field ground motions

To address the inadequate seismic performance of traditional buckling-restrained braced frame structures (BRBFS), this study introduces a novel structure, the rocking buckling-restrained braced frame structure (RBRBFS). The RBRBFS achieves effective control of main structure damage and enhances structural energy dissipation and seismic resilience by disconnecting the column feet from the foundation in the BRBFS and using friction energy dissipation devices as rocking column feet. This research aims to quantitatively assess the seismic performance and collapse safety margin of the new RBRBFS under different types of ground motions. To achieve this goal, two eight-story structures, one is traditional BRBFS and the other is RBRBFS, were designed. Incremental Dynamic Analysis (IDA) was employed, accounting for ground motion uncertainty, to conduct a comparative study of the seismic fragility of both structures subjected to near-fault pulse-like and far-field earthquake ground motions. Nonlinear dynamic analysis results indicate that under high-intensity ground motions, the RBRBFS significantly improves structural ductility and effectively controls structural damage. Compared to BRBF structures, the BRBFS exhibit a reduction of 26.5% and 18.3% in damage probability deviation under the two seismic excitations, highlighting their more stable structural response under varying seismic conditions. Furthermore, this novel RBRBFS increases the collapse margin ratio by 25% to 30%, demonstrating its higher seismic collapse resistance capacity

A more explosion-resistant bamboo fiber reinforced composite structure through balancing bamboo anisotropy

Explosion-resistance of two kinds of bamboo composite plates with different laminated structures was investigated by in-field explosion experiments. It is revealed that both unidirectional parallel bamboo strand lumber (PBSL) plates and cross-laminated bamboo (CLB) plates can resist large dynamic elastic deformation and have good anti-explosion ability. Through balancing PBSLs’ anisotropy by cross-laminated structure, the CLB plate is far superior to the PBSL in explosion resistance. In this research, the critical scaled distance is between 1.293 m/kg1/3 and 1.086 m/kg1/3 for the PBSL, while it is significantly reduced and between 0.543 m/kg1/3 and 0.407 m/kg1/3 for the CLB. Matrix cracking penetrates the full thickness of the PBSL plate and attenuates its explosion resistance, while this shortcoming is overcome by the CLB whose main damage modes are fiber fracture and spalling. The CLB is a more explosion-resistance bamboo structure.

Funerary art and electroplating: history, present and future

Electroplating is the technique of producing an artifact by electroplating a metal onto a model. This manufacturing method can be applied to produce pieces with complex shapes and a wide variety of dimensions and, mainly in the 19th century, it was used to make funerary art items. This technique is also used to produce replicas of artistic items in order to safeguard them, but also to make them public through these replicas. Although electroplating is a widely used technique, galvanoplastic sculptures present a laborious restoration process due to the difficulty of electroplating only the regions of damaged deposits and the fragile core. In order to identify the main production characteristics and damage present, with a view to a possible restoration stage, the statuary from the Santa Casa de Misericórdia cemetery in Porto Alegre was studied. Samples were taken from the mould and the electrodeposited layer of statues in different states of conservation to be analyzed by metallography. It was possible to observe the structure of the electrodeposits, the width and quantity of layers deposited and the material used to make the model.

Nut phenological development and feeding activity by true bugs as factors in the occurrence of main damage in two European hazelnut districts

Nut phenological development and feeding activity by true bugs as factors in the occurrence of main damage in two European hazelnut districts

Development of a dynamical statistical analog ensemble forecast model for landfalling typhoon disasters

In this report, the development of a Dynamical Statistical Analog Ensemble Forecast model for landfalling typhoon disasters (LTDs) and some applications over coastal China are described. This model consists of the following four elements: (i) obtaining the forecast track of a target landfalling typhoon, (ii) constructing its generalized initial value (GIV), (iii) identifying its analogs based on the GIV, and (iv) assembling typhoon disasters of the analogs. Typhoon track, intensity, and landfall date are introduced in GIV at this early development stage. The pre-assessment results show that the mean threat scores of two important damage levels of LTDs reach 0.48 and 0.55, respectively. Of significance is that most of the damage occurs near the typhoon centers around the time of landfall. These results indicate the promising performance of the model in capturing the main damage characteristics of typhoon disasters, which would help coastal community mitigate damage from destructive typhoons.

Drilling of Cross-Ply UHMWPE Laminates: A Study on the Effects of the Tool Geometry and Cutting Parameters on the Integrity of Components.

Ultrahigh-molecular-weight polyethylene (UHMWPE) is used in the defence industry mainly owing to its properties, such as excellent dimensional stability, excellent ballistic performance, and light weight. Although UHMWPE laminates are generally studied under impact loads, it is crucial to understand better the optimal machining conditions for assembling auxiliary structures in combat helmets or armour. This work analyses the machinability of UHMWPE laminates by drilling. The workpiece material has been manufactured through hot-pressing technology and subjected to drilling tests. High-speed steel (HSS) twist drills with two different point angles and a brad and spur drill that is 6 mm in diameter have been used for this study. Cutting forces, failure, and main damage modes are analysed, making it possible to extract relevant information for the industry. The main conclusion is that the drill with a smaller point angle has a better cutting force performance and less delamination at the exit zone (5.4 mm at a 60 m/min cutting speed and a 0.05 mm/rev feed) in the samples. This value represents a 46% improvement over the best result obtained in terms of delamination at the exit when using the tool with the larger point angle. However, the brad and spur drill revealed a post-drilling appearance with high fuzzing and delamination.

A study of adhesive bonding in metal–metal, metal–CFRP, and CFRP–CFRP material combinations under shear deformation: Fracture morphologies and damage mechanisms

Safe design of adhesive joining in multi-materials in engineered structures requires the accumulation of numerous experimental data on the failure behavior of various adhesively-bonded material combinations under different loading conditions. The deep understanding of mechanical performance, fracturing morphologies, and main damage mechanisms is also quintessential for accelerating the development of proper physics-based and multi-scale models for assisting the design.Towards this goal, this work presents a comprehensive characterization of the failure behavior of adhesively-bonded metal–metal, metal–CFRP, and CFRP–CFRP material combinations under global shear deformation via single lap shear testing. Thanks to a synergistic combination of measurement methods by using Digital Imaging Correlation (DIC) and 3D optical profilometry, adhesive features on the adherend after failure were quantified and the main progressive damage mechanisms were identified.The characterization performed in this work provides quantitative data that contributes to a better understanding of shear failure in adhesive bonding across different bi-material combinations. The obtained results have practical implications, including the potential to enhance adhesive bonding design, identify failure causes in adhesive joints, and develop or validate computational models capable of capturing the observed behavior in various adhesively-bonded materials under global shear deformation.

The Importance of Out-of-Office Blood Pressure Measurement, as Highlighted by the Correlation with Left Ventricular Hypertrophy in an Untreated Hypertensive Population.

Background and Objectives: Hypertensive heart disease, especially left ventricular hypertrophy (LVH), is considered to be one of the main types hypertension-mediated organ damage. Hence, the purpose of this study was to examine which method of measuring BP (office BP measurement (OBPM), 24 h ambulatory BP monitoring (ABPM), or home BP monitoring (HBPM)), can be better correlated with echocardiographic LVH in the untreated hypertensive population. Materials and Methods: This study's population consisted of 202 patients 58 ± 15 years old (40.8% males). All patients reported elevated home BP measurements for at least 3 months, but they had never been treated before for hypertension. Office and out-of-office BP measurements, including ABPM on a usual working day and seven-day HBPM, as well as 2D echocardiography, were performed. Results: In the univariate analysis, LVH was associated (p < 0.05) with a mean 24 h systolic BP (OR: 1.93, CI: 1.29-2.91), a mean 24 h diastolic BP (OR: 1.30, CI: 1.16-1.80), ambulatory daytime systolic (OR: 1.11, CI:1.01-1.82) and diastolic BP (OR: 1.13, CI:1.09-1.17), ambulatory nighttime systolic BP (OR: 2.11, CI: 1.04-4.31), and mean home systolic BP (OR: 1.05, CI:1.01-1.12). Pearson's correlation analysis showed a significant correlation between the LV mass index and the mean 24 h systolic BP (r = 0.58, p < 0.05), daytime systolic BP (r = 0.59, p < 0.05), and nighttime systolic BP (r = 0.57, p < 0.05). Most of the population with confirmed LVH presented confirmed hypertension (based on ABPM, 48.1% or HBPM, 40%). The second most dominant phenotype was masked hypertension (ABPM, 32.7% and HBPM, 23.7%). The majority (59.3%) had non-dipping status, 20.4% had a reverse dipping pattern, 13% had a dipping pattern, and only 7.3% had extreme dipping BP. Conclusions: Out-of-office BP measurement devices seemed to be superior compared to in-office. This advantage is highlighted by better correlations in the identification of LVH as well as the diagnosis of masked hypertension, a condition also highly correlated with LVH.

Evolution of Fretting-Induced Cracks and Delamination Wear on Alloy 690 Steam Generator Tubes During Mixed Fretting Regime in Air at Room Temperature

The occurrence of fretting-induced cracks and delamination wear processes in a mixed fretting regime on Alloy 690 steam generator tubes against 304L stainless steel pads was analyzed. Fretting tests in 90° cross-cylinder configuration were performed in air at room temperature. Changes in the contact conditions were evaluated using the energy ratio and the sliding ratio criteria. Damage was characterized using light microscopy, scanning electron microscopy, and optical profilometry. Vickers microindentation was applied to characterize the initial plastic deformation process. It was found that during the initial 1 × 103 cycles, plastic deformation constitutes the main damage mechanism. Thereafter, between 1 × 103 and 1 × 104 cycles, cracks nucleation and propagation accompanied by negligible wear were detected. Beyond 1 × 104 cycles, the dominant main damage mechanism consists of delamination wear assisted by cracks coalescence, and a change from a U-shaped to a W-shaped scar profile was observed in correspondence with the appearance of the delamination wear process.

DAMAGE PATTERNS OF DIFFERENT BIRDS AND RODENT SPECIES IN GRAIN STORAGES IN BAHAWALPUR, PAKISTAN

Birds and Rodents can cause significant damage to grain stores in developing countries, affecting the food security and income of small-holder farmers. Methods for assessing storage losses by rodents under small-holder conditions will help farmers and policy makers understand the impact rodents may have on food security, nutrition, and health. The present study aimed to determine the different damage patterns by birds and rodents in grain storage in Bahawalpur, Pakistan. The study was conducted between August 2021 and February 2022. Twelve grain stores were selected for the observations based on environmental conditions and storage types. Damage patterns were observed through scan sampling by directly observing the damage patterns in terms of grain spreading, fecal contamination, hair contamination, packaging injuries, and feather presence. For loss assessment, the Bowls with known quantities (about 2kg) of grains were placed within grain storage and periodically monitored for weight loss, fecal contamination, and percentage of birds and rodent- damaged grains. The bowels were weighted before and after rodents or bird attack and difference in weight were used to calculate percentages losses. Grain spreading was observed as main damage pattern by birds. Its percentage was measured as 68%, followed by fecal droppings (14%), packaging injuries (13%), and feather presence (5%). Rodents main damage pattern was also grain spreading (47%), followed by packaging injuries (23%), fecal droppings (20%), and presence of hair (10%). Estimates of grain losses in the absence of measures were 23.1% annually. These losses were reduced when rodent control was implemented. So, by implementing control methods and propers storage strategies and using good quality packaging material the rodents and birds losses can be reduced.

Experimental investigation on the effect of contact forces on uneven longitudinal wear of rail material

The effect of contact forces on rail uneven longitudinal wear was investigated using three series of rolling tests, including tests with the same tangential force and varying normal force, tests with the same normal force and varying tangential force, and tests with varying tangential and normal forces. Results indicated that the effect of tangential force on rail uneven longitudinal wear was greater than that of normal force. When the tangential force was the same, rail uneven longitudinal wear occurred under the small normal force condition. As the normal force increased, the wear rate decreased. With the same normal force, rail uneven longitudinal wear occurred under the large tangential force condition. The main damage of the unevenly worn rail was oxidative wear and fatigue wear. The oxidative wear and ploughing were more severe at the crest. Plastic deformation, the degree of grain refinement and fatigue cracks were more severe at the trough. More severe fatigue cracks at the trough lead to more severe wear and then the aggravation of rail uneven longitudinal wear.

Coastal and maritime archaeology in Cyrenaica, Libya: history, developments, site identification and challenges

Abstract The coastline of Cyrenaica, Libya, is rich in cultural heritage dating from prehistory to the modern periods. Despite the region's long-standing and strong connection to the sea, maritime archaeology remains a peripheral, but growing, branch of archaeology in Libya. This paper aims to provide an overview of the maritime projects that have been carried out in Cyrenaica in the past. Furthermore, it will highlight the main threats and damages that coastal heritage faces today and will provide some suggestions on how the discipline could develop in the future. The Cyrenaica Coastal Survey (CCS), a collaboration between the Maritime Endangered Archaeology (MarEA) project and the Department of Antiquities (DoA), Libya, will serve as a case study of an ongoing project that documents and assesses the condition of sites along the Cyrenaican coast between Tocra and Apollonia.

Review of shock wave pressure reconstruction methods in explosion field

Explosion shock wave pressure is one of the main damage parameters produced in the process of ammunition explosion, and it is also an important technical index to evaluate the damage power of ammunition. However, in the actual testing process, only a limited amount of shockwave pressure data at specific measuring points can be obtained, which cannot accurately reflect the distribution laws of the shockwave pressure propagation after the ammunition explosion. Therefore, it is particularly important to conduct reconstruction of the shockwave pressure field distribution laws based on limited measuring point data. This paper reviews the research work and related achievements obtained by researchers at home and abroad on the reconstruction of shockwave pressure distribution laws in explosion fields. The paper also elucidates the relevant application of computer tomography imaging techniques, shockwave propagation attenuation model reconstruction, and various interpolation algorithms in the reconstruction process of the shockwave pressure field. Given the current research situation both domestically and internationally, we have pinpointed the major issues that still exist in the current stage of research and proposed the key areas of focus that need attention in future research.

Rising of Dynamic Polyimide Materials: A Versatile Dielectric for Electrical and Electronic Applications.

Polyimides (PIs) are widely used in circuit components, electrical insulators, and power systems in modern electronic devices and large electrical appliances. Electrical/mechanical damage of materials are important factors that threaten reliability and service lifetime. Dynamic (self-healable, recyclable and degradable) PIs, a promising class of materials that successfully improve electrical/mechanical properties after damage, are anticipated to solve this issue. The viewpoints and perspectives on the status and future trends of dynamic PI based on a few existing documents are shared. The main damage forms of PI dielectric materials in the application process are first introduced, and initial strategies and schemes to solve these problems are proposed. Fundamentally, the bottleneck issues faced by the development of dynamic PIs are indicated, and the relationship between various damage forms and the universality of the method is evaluated. The potential mechanism of the dynamic PI to deal with electrical damage is highlighted and several feasible prospective schemes to address electrical damage are discussed. This study is concluded by presenting a short outlook and future improvements to systems, challenges, and solutions of dynamic PI in electrical insulation. The summary of theory and practice should encourage policy development favoring energy conservation and environmental protection and promoting sustainability.

Carburizing Rate of Pyrolysis Furnace Tube in Long-term Service

The high-temperature working environment of ethylene pyrolysis furnace tubes makes carburization one of the main damage mechanisms, and carburization also leads to the degradation of tube material properties and failure. It is important to study the carburization rate of long-term service furnace tubes for the evaluation of long-cycle use and carburization detection. In this paper, the relationship between carburization rate and carburization time is studied by low-pressure vacuum carburization of Cr35Ni45Nb alloy tubes with different service life (new tubes, two years, three years, and six years) in the field, aiming to provide a scientific basis for the remaining life prediction and carburization inspection for the tube material.

Deterioration analysis of historical village house structure in Mersin Kanlıdivane archaeological area by UAV method

The village house located in the Mersin Kanlıdivane archaeological site is one of the oldest settlements in the ruins, built in the second century. The house is mainly built of a yellowish beige limestone. This stone, which is the main material of the building, shows many deterioration patterns today. The aim of the study is to determine the dominant deterioration pattern of the stones in the village house structure in the Mersin Kanlıdivane archaeological site and to investigate the source of the deterioration. In order to investigate the deterioration patterns in the structure, the images obtained by UAV photogrammetry were interpreted and the types of deterioration were mapped. In the study, it is seen that even the types of material problems based on the smallest detail can be determined based on virtual visual inspection, thanks to UAV photogrammetry, without observing the structure in situ with UAV photogrammetry. The findings obtained in the study shows that the color change and surface loss deterioration on the stone surfaces has reached advanced levels as a result of the structure's exposure to the strong climate-induced sun and water effects for centuries. The results of the study show that the main damage observed on the stone surface of the structure is caused by the erosion by the effect of water. Restoration methods should be tried to stabilize the deterioration and replace the most degraded stones. It is recommended to use water-repellent surface coatings to protect the natural stone, especially against the intense water effect in the building.

High-temperature behaviour and interfacial damage of CGI: 3D numerical modelling

Superior mechanical and thermal properties, high wear resistance and a competitive price of compacted graphite iron (CGI) have made it an integral part of industry worldwide. In its applications in automotive engines, high-temperature environments cause thermal expansion that can result in emergence of interfacial damage in CGI. Although graphite-matrix interfacial damage is considered the main damage mechanism that can lead to total fracture of CGI, extensive research on CGI has not yet fully investigated this phenomenon at the microscale, especially under pure thermal loading. This paper focuses on the high-temperature performance of CGI and the onset of damage in graphite in thermal cycles. Three-dimensional numerical models are developed, with a single graphite inclusion embedded in a unit cell of the metallic matrix. Elastoplastic behaviour is considered for both phases in simulations. The effects of morphology and orientation of graphite inclusions on a response of an entire unit cell to thermal loading are investigated. Also, the influence of periodic and fully-fixed boundary conditions on the damage behaviour of CGI is discussed. The results can give a better understanding of the fracture mechanisms of CGI exposed to elevated temperatures.

The strength characteristics and competitive failure mechanism of primary coal-rock combination considering interface damage quantity

The strength and failure characteristics of primary coal-rock combinations are essential in coal-rock dynamic hazards prevention and coalbed methane drainage. Current studies simplify the primary coal-rock interface as smooth, which is inconsistent with the fact that there is a complex structure at the actual primary coal-rock interface. To study the influence of actual primary coal-rock interfaces on the strength and failure characteristics of primary coal-rock combinations, large primary coal-rock combinations from the Shendong Baode coal mine were collected, processed into standard samples, and scanned by industrial CT to reconstruct the 3D model of the primary coal-rock combinations interface. The probability density function of interface microelement inclination angle was statistically obtained, and the progressive damage model of the interface was established based on the density function. Then, uniaxial compression tests with acoustic emission localization were conducted on primary coal-rock combinations with different interface inclination angles. Finally, the competitive failure mechanism was used to analyze the influence of interface damage quantity on the strength characteristics and failure mode of the primary coal-rock combination. The results show that the primary coal-rock combination interface has a complex microstructure, and the inclination of the interface microelements is right-skewed distributed between 0 and 90°, with a plurality of 16°, conforming to the Rayleigh-Beta joint distribution. The coal and interface competed for the damage quantity of the primary coal-rock combination under uniaxial compression. As the interface inclination increased, the interface damage quantity increased, but the strength and energy density decreased, and the main damage gradually changed from the coal to the interface.

Assessment of the residual life of turbine runners with operational defectiveness

The residual life of the runners of hydraulic turbines in the presence of operational defects is estimated. The main problems of the operation of hydraulic turbines associated with technological defects and exhaustion of the standard resource are described. The main requirements for initial data to be used in estimation of the residual resource and the requirements for predicting the residual resource of runners based on the results of surveys and analysis of their technical condition are specified. We have classified and briefly described the applied approaches and techniques used in estimation of the residual resource. The main damaging factors affecting the residual life of the runners are revealed: deformation aging of the metal, cavitation, corrosion and fatigue damage to the elements of runners. The most characteristic defects are divided into three groups: zones of cavitation erosion; corrosion-fatigue cracks; and weld defects. Particular attention is paid to corrosion-fatigue cracks identified using flaw detection. The mechanism of crack formation and the most probable location of the cracks in the runner are shown. Statistical data on the number of cracks at the onset of the runner operation and at the time of shutdown maintenance are presented. The main statistical parameters of the sample and the parameters of crack size distributions including the distribution law are determined. The distribution law is exponential for the crack length parameter; whereas for the crack opening width it is log-normal. The revealed multidirectional cracks are located at the surface, subsurface or inner layer of the metal. They arise from operational defects (ulcers, craters, undercuts or delamination) and grow during operation of the turbine units. We also present the design schemes of elements with cracks used for quantification of resources according to the criteria of fracture mechanics. The results of calculations for static and dynamic crack resistance are presented as the dependence of stress intensity factors on the crack size. The levels of the total accumulated damage to the runners, the values of the residual life at the stage of crack nucleation and development were determined for 11 hydraulic units in the «start-stop» and «working» cycles. The main conclusion is that the total operating time of the hydraulic turbine runners significantly exceeds the standard operating life, while the residual resource is insufficient for a further period of long-term operation.