Criterion Of Damage Research Articles

Study of Radiosensitivity and Induction of Radiation Adaptive Response in Peripheral Blood Lymphocytes of Patients with Oncological Diseases Using the Micronuclear Test.

Radiosensitivity to low and medium doses of X-ray radiation and the ability to induce a radiation adaptive response (RAR) of lymphocytes during in vitro irradiation of peripheral blood of patients with cancer were studied. The criterion for cytogenetic damage was the frequency of micronuclei (MN) in cytochalasin-blocked binucleate lymphocytes in culture. It was found that the spontaneous level of cytogenetic damage in the lymphocytes of patients was 2.6 times higher than in healthy volunteers, and there was also significant interindividual variability in values compared to the control cohort. There were no differences in mean values for radiosensitivity to low and medium doses of X-ray between the study groups. There was no correlation between the spontaneous level of MN in lymphocytes and the radiosensitivity of individuals in both groups. RAR was induced with the same frequency and to the same extent in lymphocytes from both patients and healthy individuals.

A tensorial energy-release-rate based anisotropic damage-plasticity model for concrete

This paper proposes an anisotropic damage model for concrete to capture its plasticity and damage behavior effectively. Utilizing the framework of continuum damage mechanics, the model considers the influence of plastic Helmholtz free energy on damage evolution. This approach explicitly deduces damage-related thermodynamic forces without resorting to assumptions such as strain equivalence or energy equivalence. The proposed model employs tensile and compressive damage tensors to describe the development of anisotropic damage in concrete. The solution for plastic strain utilizes the empirical plasticity model. Furthermore, a unified evolutionary criterion for isotropic and anisotropic damage is also established, incorporating damage yield functions and orthogonal flow laws. Numerical simulations are conducted to validate the model’s ability to reproduce typical nonlinear behaviors of concrete structures under various load conditions.

Predicting mechanical failure of polycrystalline dual-phase nickel-based alloys by numerical homogenization using a phase field damage model

Brazing of nickel-based alloys plays a major role in the assembly of turbine components, e.g., abradable sealing systems. In a brazed joint of nickel-based alloys a composition of brittle and ductile phases can be formed if the brazing conditions are not ideal. This heterogeneous microstructure is a crucial challenge for predicting the damage behavior of a brazed joint. The initiation and evolution of microdamage inside of the brittle phase of a virtual dual-phase microstructure representing the material in a brazed joint is studied by means of numerical simulations. A phase field approach for brittle damage is employed on the microscale. The simulation approach is capable of depicting phenomena of microcracking like kinking and branching due to heterogeneous stress and strain fields on the microscale. No information regarding the initiation sites and pathways of microcracks is needed a priori. The reliability of calculating the effective critical energy quantities as a microstructure-based criterion for macroscopic damage is assessed. The effective critical strain energy density and the effective critical energy release rate are evaluated for single-phase microstructures, and the approach is transferred to dual-phase microstructures. The local critical strain energy density turns out to be better suited as a model input parameter on the microscale as well as for a microstructure-based prediction of macroscopic damage compared to a model employing the energy release rate. Regarding the uncertainty of the model prediction, using the effective critical energy release rate leads to a standard deviation which is five times larger than the standard deviation in the predicted effective critical strain energy density.

The fully coupled thermo-mechanical dual-horizon peridynamic correspondence damage model for homogeneous and heterogeneous materials

To accurately address the thermally induced dynamic and steady-state crack propagation problems for homogeneous and heterogeneous materials involving crack branching, interfacial de-bonding and crack kinking, we propose the fully coupled thermo-mechanical dual-horizon peridynamic correspondence damage model (TM-DHPD). To this end, the integral coupled equations for TM-DHPD are firstly derived within the framework of thermodynamics. And then, the alternative dual-horizon peridynamic correspondence principle is used to derive the constitutive bond force state, heat flow state and their general linearizations. Moreover, the unified criterion for bond damage is proposed to characterize the internal bond damage in a single material and the interface bond damage in dissimilar materials. To ensure convergence and accuracy, the coupled equations are solved using the standard implicit method without the use of artificial damping. In both homogeneous and heterogeneous materials, some representative and challenging numerical cases are examined, such as dynamic crack branching in a centrally heated disk and multiple interface failure of thermal barrier coating. The numerical results are in good agreement with the available experimental results or the previous predictions, which shows the great potential of the proposed TM-DHPD in addressing the physics of numerous thermally induced fractures in the real-world engineering problems.

Criterion of damageability of structural materials

The work considers the quantitative assessment of the accumulation of scattered damage as a multi-scale and multi-stage phenomenon under elastic-plastic loading, which leads to the degradation of the physical and mechanical properties of structural materials, which is expressed in the change of the modulus of elasticity G and E. The paper proposes a criterion of damage, containing the effect of damage on the service life of the structure under an external complex load. The physics of the process of kinetics of damage accumulation suggests a factor of structural changes as a result of loosening of the material under load for separation and shearing of the representative element in the most loaded section.

Statins and highly sensitive cardiac troponins: cardiotoxicity or cross-reactivity?

To date, hypolipidemic drugs of the statin group are among the most popular therapeutic agents used for the prevention and treatment of the most common worldwide atherosclerotic cardiovascular diseases (CVD). Therefore, considerable attention of researchers is focused on statins to study the additional effects of these drugs, which is accompanied by the discovery of new mechanisms of action and properties that should be taken into account to optimize the tactics of managing patients with CVD. In addition to the key lipid-lowering effect of statins associated with the inhibition of the ratelimiting enzyme (3-hydroxy-3-methylglutaryl-coenzyme A reductase), researchers report a variety of other properties of these drugs. Important circumstances contributing to the disclosure of new effects of statins are: improvement of research methods, and first of all, their sensitivity and specificity; the discovery of new molecules and molecular pathways that may be affected by statins. In general, the currently established numerous non-lipid effects of statin drugs can be divided into two groups: favorable and side effects, which must be taken into account when managing patients with CVD and comorbid diseases. Thanks to recent studies using modern clinical diagnostic cardiomarkers (highly sensitive cardiac troponins (CT)), molecular genetic and morphological methods, potential cardiotoxic properties of statin group drugs have been identified. Of particular concern are the data on a statininduced increase in the concentration of highly sensitive CT, which are a key and generally recognized criterion for myocardial damage. In this article we discuss possible mechanisms of increasing the concentration of CT and cardiotoxic effects when using statins.

Mechanisms and Models of Attenuation of Shock Waves through Rock Formations

Rock bursts have become one of the worst disasters in deep mines, and the safety of roadways is affected by stress waves generated when hard roofs fracture. Pictures of a mine site were collected using the Hujiahe mine as a case study. The damage characteristics of the roadway were analyzed and the damage process was reproduced using numerical simulation software. The attenuation characteristics of the strength of the shock wave as it passes from the impact shock source to the roadway are summarized. Based on the stress wave transmission mechanism and geological characteristics, a “shock wave attenuation model through rock formations“ was established to analyze the transmission characteristics of impact stress under the composite roof structure. The strength criterion and energy balance equation for roadway damage under the action of shock waves are derived. This work provides a reference for roadway support under similar conditions and can be generalized and applied elsewhere.

Anti-explosion performance analysis of marine interdiction system based on ALE method

As a security protection system, the marine interdiction system can be set up outside the port to provide security protection for the ships and facilities there as well as to prevent explosions and ship collisions. This paper uses the Arbitrary Lagrangian Euler (ALE) method in ANSYS LS/DYNA to simulate a blast for an interdiction system close to the water’s surface. The simulated shock wave overpressure is extracted and fitted, and when compared with the empirical formula, it is discovered that the trend and value are in good agreement. In the case of controlled calculation scale, closer to the real situation and only consider the explosion transient effect, analysis of the dynamic reaction of the interdiction system under various operating situations to test its anti-explosion performance would help to confirm the validity of the proportional burst distance as a criterion for near-water explosion damage. The safe distance for a 500 kg TNT charge is 4.62 m, and the safe distance for a 1500 kg TNT charge is 6.37 m, when the proportional burst distance reaches 0.5, some of the cable tension reaches the breaking tension level at this moment, and foam floating balls appear to fail for some elements, but the system as a whole is still in a safe state. The research will also provide support for the optimization of the interdiction system and also provide support for the optimization and development of the marine interdiction system.

PROSPECTIVE METHODS OF USING ENTOMOPHAGES IN PROTECTING MAIZE AND SUNFLOWER FROM APHIDS IN THE CONDITIONS OF KARAKALPAKSTAN

The article presents the types of aphids that develop and cause damage to maize and sunflower crops in the conditions of Karakalpakstan, the developing type of each species, the period of coming to the field, the damage it causes, and the criterion of economic damage. The biological effectiveness of the natural predator, eaters, and golden-eyed entomophagus cultivated in biolaboratories was determined in controlling aphids, and the technology of using this predator was studied. KEYWORDS: sucker, pest, entomophagous, predator, eater, biolaboratory, biological efficiency, economic damage criterion, migration.

Comparison of Cattle Housing Systems Based on the Criterion of Damage to Barn Equipment and Construction Errors.

Simple SummaryAs a result of many years of use, dairy cattle barns are subject to gradual wear and degradation. Damage to technical equipment can be identified in many areas in the barn. These areas are used by dairy cattle, so it is important to recognize the problem of damage and the associated health risks for animals. The problem of damage to internal equipment (e.g., damage to the floor, partitions between lying stalls, feed ladders, drinking bowls) applies to both tie-stall and freestall barns, which are the most common in dairy farms. Such premises became an inspiration to compare barns with a tie-stall system, a freestall system and their individual areas (lying, feeding, milking and social) in terms of the amount of damage but also construction errors. Most damage per one barn was found in the feeding area of objects with a tie-stall housing system. More cow health problems (e.g., laminitis, hoof problems) were identified in the barns with the freestall housing system. Equipment failures and construction errors may disrupt efficient and animal-safe dairy production in the barn. The results of the research study may be an incentive for farmers to check the barns in terms of their technical wear.Dairy cattle housing systems are the subject of numerous studies, in which a strong emphasis is placed on the comparison of animal welfare, animal behavior, production indicators and labor inputs. Dairy cattle housing systems are linked to specific livestock buildings, which is a prerequisite for undertaking studies comparing barns and their technical equipment. The aim of the study was to compare barns with two types of housing systems, i.e., tie-stall and freestall, including the identification of technical wear in various areas used by animals. This objective was linked to the assessment of animal health problems in livestock facilities. The research covered 38 dairy farms, 19 of which kept cows in the tie-stall system and 19 in the freestall system. The barns in these farms were examined for technical damage and construction errors, assessed in four areas: lying, feeding, milking and social. The research results confirmed significant differences in the degree of damage to technical equipment in individual areas of barns and between barns with tie-stall and freestall housing systems. The conclusions indicate the need to link the degradation of barns and their technical equipment, as well as design errors with the evaluation of dairy cattle welfare in future studies.

Fragment behavior of concrete slab subjected to blast loading

In this study, concrete slabs subjected to blast loading with 1.5 kg explosive B at different stand-off distances were investigated to study the fragment behavior of concrete slabs. Furthermore, the particle size of the concrete fragments after the explosion was measured. The erosion criterion of coupling tensile damage and the maximum principal strain was introduced to calculate the fragment behavior of a concrete slab subjected to blast loading. The validity of the numerical calculation model was verified by comparison with the experimental data. Moreover, the concrete slab fragment behavior with different charge masses and stand-off distances was analyzed. Finally, a fragment model of the shock wave over-pressure peak, shock wave energy, charge mass, and stand-off distance under blast loading was established. This model can predict the fragment degree of a concrete slab subjected to blast loading by considering the over-pressure peak and energy of the shock wave as criteria.

Study on electrostatic discharge (ESD) characteristics of ultra-thin dielectric film

Electrostatic discharge (ESD) event usually destroys the electrical properties of dielectric films, resulting in product failure. In this work, the breakdown characteristic of machine mode (MM) ESD on three different nano size films of head gimble assemble are obtained experimentally. The breakdown voltage and thickness parameters show a positive proportional relationship, but they are generally very low and have large discrete characteristics (∼30%). The maximum and minimum breakdown voltages of the tested samples are 1.08 V and 0.46 V, which are far lower than the requirement of the current standard (25 V). In addition, the judgment criterion of product damage is given, and the relationship between discharge voltage polarity, initial resistance and breakdown voltage is studied. Finally, the theoretical analysis of the breakdown characteristic law has been given.

Strain‐based fatigue criterion for rubber damage under multimode loadings

AbstractAn accurate prediction of the fatigue life of a rubber product is based on a criterion. Since strain can be measured directly in rubber components during a test, it would help design engineers improve product performance effectively if the strain‐based damage criteria can achieve high accuracy. Hence, the experimental data on the AE42 and AE2 specimens were utilized to test the suitability of the proposed damage criterion for rubber materials. The criterion includes three principal components determined by both a strain range and a current strain. Data from AE42 specimens, made from styrene‐butadiene rubber, contained 40 cases, that is, tension, torsion, and tension‐torsion loadings. An S‐N curve was obtained, with a scatter band of 0.7 and a coefficient of determination R2 of 0.81. The curve could be useful at the design stage. A sample of AE2, made from natural rubber filled with carbon black, showed the location and orientation of the crack in a nonproportional case. The predicted location of the fatigue crack was consistent with the experimental observation and the crack orientation matched the experimental measurement, that is, the predicted angle of 33.4° versus the measurement of approximately 40°. It would be possible to combine the proposed approach with the critical plane method in nonproportional loadings to save significant CPU time: using the proposed approach to find the critical loading range and then using the critical plane method to find the maximum value of the required damage variables. More engineering cases are needed to further verify this proposed criterion.

Investigation on fatigue damage equivalence probability for the structure with similar fatigue hazardous detail parts

Fatigue damage of a whole structure with multiple similar fatigue hazardous detail parts is unclear. This paper focuses on the concept of quantified fatigue damage for the structure with similar fatigue hazardous detail parts by using the probability method and fatigue failure probability of the severe load spectrum. The probability criterion and calculation method of equivalent damage with different load spectra were proposed. The fatigue life probability distribution of the severe load spectrum was analyzed, and the acceleration ratio was defined by the similar details number of fatigue cracking in combination with the fatigue failure probability characteristics of the severe load spectrum. The results show that there is good agreement between the similar details number range of fatigue cracking in two load spectra, which means they are considered to be equivalent. The ratio of the sum of two similar details number ranges is used as acceleration ratio to evaluate the severe load spectrum. The application of this study in the statistical sense of engineering structure fatigue failure is more convincing.

Prognostic value of determination of matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1 in follicular fluid in patients in vitro fertilization programs

Aim. To determine the prognostic significance of matrix metalloproteinase-1 (MMP-1) and tissue metalloproteinase-1 inhibitor (TIMP-1) in the follicular fluid (FF) in patients with infertility to improve the effectiveness of in vitro fertilization (IVF) programs.
 Materials and methods. A study of MMP-1 and TIMP-1 in the FF was conducted in 38 patients with infertility in IVF programs. According to the genesis of infertility, the patients were divided into 2 groups. The 1st (control) group included 20 patients with tubal-peritoneal infertility (code N97.1 according to the International Classification of Diseases of the 10th revision ICD-10). The 2nd group (the main one) included 18 patients with tubal-endocrine infertility (ICD-10: N97.1, N97.0, N97.8). The choice of the ovulation stimulation protocol was made taking into account the anamnesis, previously applied protocols, control over the outcome and final result of IVF programs was developed: a protocol with gonadotropin-releasing hormone agonists was used in 20 patients, and a protocol with gonadotropin-releasing hormone antagonists was used in 18 patients. The effectiveness of IVF programs was 26.3%, the frequency of live births was 26.3%. During the puncture of the follicles, FF was taken and the levels of MMP-1 and TIMP-1 were determined in it by the method of quantitative solid-phase enzyme immunoassay of the sandwich type on an automatic flatbed photometer MultiskanFC (2012). The obtained information was subjected to statistical analysis using the Statistica 10.0 application program.
 Results. The level of MMP-1 and TIMP-1 in the FF is an individual indicator and is associated with clinical and anamnestic characteristics. The average level of MMP-1 is 4.9 ng/ml. With negative IVF outcomes, it was 6.11.3 ng/ml, with positive outcomes 1.40.1 ng/ml. The content of MMP-1 in women with tubal-peritoneal infertility genesis of 7.91.7 ng/ml indicates a residual inflammatory process in the follicle. The average level of TIMP-1 was 2462.264.3 ng/ml. The indicator increases: with age (2535.0125.7 ng/ml), duration of infertility (2611.5126.7 ng/ml), due to surgical interventions on the reproductive organs (2800122.7 ng/ml) and in patients with tubal-endocrine genesis of infertility (2550126.7 ng/ml), which indicates fibrosclerotic changes in the follicles and ovarian tissue.
 Conclusion. The level of MMP-1 in the range of 1.31.4 ng/ml should be considered a criterion for the successful onset of pregnancy in IVF programs. The criterion of subclinical damage to the collagen matrix in the FF is the level of MMP-1 6.1 ng/ml or higher; it can be considered as an unfavorable prognostic factor for the outcome of IVF. The level of TIMP-1 in the range of 24002450 ng/ml should be considered a criterion for the successful onset of pregnancy in IVF programs. The probability of a negative outcome of IVF is in the range of 15002300 ng/ml (inability to level the effects of MMP-1 with these indicators), while the level of 2696 ng/ml and higher in tubal-endocrine genesis of infertility reflects a high degree of fibrosclerotic changes in ovarian tissue and can be considered as an unfavorable prognostic factor of IVF outcome.

Prediction of the Onset of Failure in Elastomeric Solids With Weld Lines Being Represented as Localized Regions of Lower Density

Abstract We study the initiation of damage in a polymeric body in which there is a line defect due to the formation of a “weld line” that occurs when two polymer streams join together and then solidify. We show that damage initiates in the region of weakness, namely the “weld line” based on a criterion for damage that was developed earlier. We also show that if there are other stress concentrators also additionally present, such as a hole, then there is a competition between the stresses induced due to the weakness and the stress as a consequence of the stress concentrator (in this instance a hole). This study adds more credence to the criterion for the initiation of damage that is based completely on knowledge of information at the current configuration of the body, that is, the criterion for damage is not based on the value of quantities that also need information based on a reference configuration such as the stress or strain.

Kinetics of Plastic Deformation Localization Bands in Polycrystalline Nickel

Jerky flow has recently aroused interest as an example of complex spatiotemporal dynamics resulting from the collective behavior of defects in Al- and Mg-based alloys under loading. This paper presents the results of the study of the macroscopic strain localization kinetics in Nickel 200 (99.5 wt % purity). Uniaxial tension of flat samples is monitored at room temperature in the load–unload mode at a constant strain rate and total deformation increment up to 5%. The stress–strain curves reveal jerky flow from the yield point to the formation of the neck. The digital speckle correlation method evidences the movement of localized plastic deformation bands under the conditions of the Portevin–Le Chatelier effect (PLC). It is shown that stress drops during jerky flow in Ni are accompanied by the formation of morphologically simple single PLC bands. It is established that, with an increase in total deformation, the number of PLC bands and their velocity of motion along the sample decrease, while their time period increases. Moreover, an increase in total deformation leads to an increase in the parameters of the force response (i.e., time period and stress drop magnitude). It is found that the criterion of damage for PLC bands as a function of the total strain has a sigmoidal shape.

Considerations regarding liver current pathology

This work presents reasoning about liver pathology. Liver pathology is an area of interest due to the growing number of medical cases worldwide. The factors associated with the appearance of this pathology are those that relate to individual lifestyle. Liver pathology studies are performed up to the biomolecular level, involving cytochrome P450 2E1 (CYP2E1). With a normal liver, subject to aging and the aforementioned risk factors, there are changes in liver structure, which often can lead to changes arising from nonalcoholic hepatic steatosis (NASH). Under certain circumstances this degenerates into chronic hepatitis, which often goes undiagnosed and this can lead to liver cirrhosis. Due to gradual changes in the liver, medical interventions are often delayed. Importantly, structural analysis of microscopically processed liver fragments will reveal changes in all structural elements of the liver, from lipid loading in hepatic steatosis to inflammatory, necrotic, destructive, fibrotic changes in liver cirrhosis, including somewhat similar changes in types of chronic hepatitis. The presented images and the described structural changes in the liver are an important criterion for liver damage, including preclinical pathology.

Time effect and prediction of broken rock bulking coefficient on the base of particle discrete element method

Bulking characteristics of gangue are of great significance for the stability of goafs in mining overburden in the caving zones. In this paper, a particle discrete element method with clusters to represent gangue was adopted to explore the bulking coefficient time effect of the broken rock in the caving zone under three-dimensional triaxial compression condition. The phenomena of stress corrosion, deformation, and failure of rock blocks were simulated in the numerical model. Meanwhile, a new criterion of rock fragments damage was put forward. It was found that the broken rock has obvious viscoelastic properties. A new equation based on the Burgers creep model was proposed to predict the bulking coefficient of broken rock. A deformation characteristic parameter of the prediction equation was analyzed, which can be set as a fixed value in the mid- and long-term prediction of the bulking coefficient. There are quadratic function relationships between the deformation characteristic parameter value and Talbot gradation index, axial pressure and confining pressure.

Determining initial damage state of confined masonry wall

A masonry wall can withstand the compressive, tensile, and shear forces, besides that, a masonry wall can add rigidity to the building structure. The stiffness contributed by the masonry wall can influence the stiffness of the global structure. The contribution of stiffness to masonry walls is linear until the walls are damaged. The linear limit of the behaviour of masonry infill reinforced concrete portal can be used as the first criterion of damage (damage state). This study aims to determine the limit criteria for damage to reinforced concrete masonry wall buildings. The types of bricks used are normal bricks, Z bricks, Z hook bricks. The portal structure of masonry infill reinforced concrete was analyzed using the stiffness approach in the matrix formulation, where the wall stiffness was assumed to be a strut. The strut stiffness is determined based on the masonry panel shear test. The amount of lateral deformation on the portal when the internal shear force on the strut element reaches the wall shear strength limit is used as a limit for the linear behaviour of the masonry-filled reinforced concrete portal.