Stages Of Fatigue Research Articles

Fatigue behaviors of graphene reinforcing concrete composites under compression

This paper first studies the fatigue behaviors of multi-layer graphene (MLG) reinforcing reactive powder concrete (RPC) under compressive loads. It provides experimental results including fatigue life, fatigue deformation development, damage index and energy absorption, investigates temperature difference inside concrete composites by monitoring hydration temperature at different locations, and studies micro-structures of internal weakness of RPC via Scanning Electron Microscope (SEM), Energy-Dispersive Spectroscopy (EDS) and Digital Image Processing (DIP) method. The results show that, incorporation of MLG significantly reduces internal weakness of RPC. Specifically, MLG decreases temperature difference and thermal stress inside concrete composites, refines harmful pores in fatigue cracking zone (diameter above 100 nm), and stabilizes chemical composition of interfacial transition zone. By bridging micro-cracks and bonding with hardened cement matrix, the sheet-formed MLG slows down the generation of microcracks at creep-fatigue coupling stage, delays the start of fatigue stage, and increases fatigue failure strain. Consequently, even at 0.075 wt% MLG content, the fatigue life, energy absorption, and damage index of RPC are increased up to 49.3% (in terms of logarithm), 333.1%, and 22.23%, respectively. In addition, based on strain increase per circle at the creep-fatigue coupling stage, a fatigue life prediction equation is derived, which provides an approach to estimating the fatigue reliability of the structures using this composite.

Numerical study of the crack growth variability under irregular loading

Estimation of the scatter of the durability at the second stage of fatigue, namely at the stage of crack propagation is a problem of scientific and obvious practical importance: machines operate according to their technical condition, which means monitoring of the actual crack length during their service life. The limits of the spread of the strength values at the stage of crack propagation in aluminum samples are studied using published data and a previously developed model. In view of the great importance of this problem, a special simulation model was used to generate the extrema of a random sequence based on target Markov matrices. On the one hand, this simulation method guarantees the characteristic traits of real sequence in exploitation (TWIST standard in this example). On the other hand, it contains reasonable randomness — these two parts together provide an opportunity to study the variability of the crack growth rate. For the simulation experiment, literature data on aluminum and steel samples were used along with popular fatigue crack growth models (Paris, Foreman and Willenborg models). In addition, the Miner’s summation rule was quantitatively tested to estimate the crack growth resistance coefficient under various loads. The agreement with the literature experimental data is shown. Preliminary data on the effect of the type of loading (random or block) on the durability are given on the basis of scientific literature data. The proposed simulation method can be useful for testing various models. It is also intended to develop an experimental design for laboratory testing in the future.

Evolution of fracture mechanics parameters relevant to narrow notch increment as a measure of fatigue damage accumulation

An unconventional destructive method for quantitative assessment of fatigue damage accumulation in the stress concentration zone is proposed and verified. Damage accumulation in strain gradient area is reached by preliminary push–pull loading of plane specimens with open holes. Narrow notches, emanating from the hole edge at different stages of low-cycle fatigue, serve to manifest a damage degree. These notches are inserted under constant external load. Deformation response to local material removing is measured by electronic speckle pattern interferometry (ESPI) in terms of in-plane displacement components. It is shown that normalized values of the notch mouth open displacement (NMOD), the stress intensity factor (SIF) and the T-stress can reliably be used as current damage parameter. Numerical integration of curves, describing an evolution of fracture mechanics parameters, produces the damage accumulation function in an explicit form. It is established that all three fracture mechanics parameters give close results.

Effects of cross-slip activity on low-cycle fatigue behavior and dislocation structure in pure aluminum single crystals with single-slip orientation

Fully reversed tension-compression low-cycle fatigue tests were performed at room temperature (RT) and 77 K on single-slip-oriented pure aluminum single crystals having different Schmid factor (SF) values (0, 0.14 and 0.24) for the cross-slip system under constant plastic shear-strain amplitudes. Cyclic deformation curves showed no stress saturation at RT, regardless of the applied strain amplitude. The cyclic deformation behavior at RT was as follows: initial hardening, softening and secondary hardening in the specimens with non-zero SF, whereas the specimens with SF = 0 exhibited monotonic hardening. However, all the specimens formed and developed the cell structure from the early stage of fatigue. On the other hand, no differences were observed in the cyclic deformation of the three specimens at 77 K. Shear stress amplitudes revealed initial hardening followed by saturation at any shear strain amplitudes applied, and a plateau stress region with a value of 42 MPa appeared in the cyclic stress-strain curve obtained at 77 K. Dislocation structures in the tested specimens were almost identical to those observed in single-slip-oriented pure Cu single crystals fatigued at RT.

Fatigue damage monitoring and analysis of aged asphalt concrete using acoustic emission technique

This paper presents an Acoustic Emission characterisation of the damage behaviour of asphalt concrete subjected to bending fatigue loading. An experimental campaign is carried out on an old asphalt concrete extracted from an in-service highway pavement, built-in 2001. Tests were performed in strain-controlled mode with an amplitude of 175 µstrain, a frequency of 25 Hz, and at 10°C. Failure criteria based on modulus decrease are analysed to determine the fatigue lifespan. Acoustic emission measurements are used to investigate the damage and failure processes. A network of eight piezoelectric sensors was used to acquire the acoustic signals. Therefore, different fatigue stages are identified based on the temporal evolution of acoustic activity. Hence, the event’s spatial location is presented to show the crack path propagation. The results show that sensors located at the bottom of the sample register more acoustic activity. The locations of acoustic events were in good agreement with the mechanical background calculations.

Residual stresses near cold-expanded hole at different stages of high-cycle fatigue by crack compliance data

Experimental method for a characterization of high-cycle fatigue evolution of residual stress near cold-expanded hole is developed and implemented. The technique is based on simultaneous measurements of deformation response to narrow notch, inserted in residual stress field, on opposite specimen’s faces by electronic speckle-pattern interferometry (ESPI). Two-side measurements of notch opening displacements are performed when a single notch, emanating from cold-expanded hole edge, is inserted. The transition from in-plane displacement component to residual stress intensity factor (SIF) values follows from the relationships of modified version of the crack compliance method. The approach provides a difference in residual stress values referred to mandrel entrance and exit surface. Notches are inserted at different stages of low-cycle fatigue without applying external load. The results obtained describe fine nuances of residual stress evolution, which cannot be considered as monotonic relaxation.

The Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes

Through scientific research, it has been found that rapid weight loss significantly affects the physiological and physical aspects of athletes. Therefore, the researcher believes that the athlete's weight loss by this amount in a very short period leads to a decrease in the physiological and physical condition, a weakness in the athlete's strength, reaching the stage of fatigue and exhaustion, and a negative impact on the level of physical and health fitness and performance level in the competition, which will also weaken his ability To resist and reduce his attention, as a sport requires the use of his maximum physical and psychological strength and ability to achieve victory and reach the highest levels. This research is considered within the applied research that the researcher hopes to benefit those interested in sports nutrition. study is one of the recent studies dealing with the role of Carnitine in improving blood fats in athletes. METHODS: This research is considered within the applied research that the researcher hopes to benefit those interested in sports nutrition. study is one of the recent studies dealing with the role of Carnitine in improving blood fats in athletes. RESULTS: researcher attributes the statistical differences and the improvement rates of the group that used aerobic exercises in the variables under investigation to the effect of the training program applied to them, which contained exercises that resulted in a high level of those variables, and this improvement is due to the continuity of their regularity within the training program. Which led to the occurrence of the adaptation process in training and thus the rise in these variables. Conclusions: presence of significant differences between the previous and post-measurement of the control group in the measurements of blood fats. valid post measurement of the boxing players in the Mansoura University team. There are differences in the rates of change between the pre-and post-measurements of the control group in the variables under investigation, the valid post-measurement, where the change percentages ranged from (3.885%) to (10.769%). presence of significant differences between the pre-and post-measurement of the experimental group in measurements of blood fats. valid post measurement is for athletes. How to Cite this Article Pubmed Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. SRP. 2021; 12(3): 361-368. doi:10.31838/srp.2021.3.55 Web Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. http://www.sysrevpharm.org/?mno=54749 [Access: March 30, 2021]. doi:10.31838/srp.2021.3.55 AMA (American Medical Association) Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. SRP. 2021; 12(3): 361-368. doi:10.31838/srp.2021.3.55 Vancouver/ICMJE Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. SRP. (2021), [cited March 30, 2021]; 12(3): 361-368. doi:10.31838/srp.2021.3.55 Harvard Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha (2021) Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. SRP, 12 (3), 361-368. doi:10.31838/srp.2021.3.55 Turabian Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. 2021. Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Reviews in Pharmacy, 12 (3), 361-368. doi:10.31838/srp.2021.3.55 Chicago Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. The Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. Systematic Reviews in Pharmacy 12 (2021), 361-368. doi:10.31838/srp.2021.3.55 MLA (The Modern Language Association) Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha. The Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Athletes. Systematic Reviews in Pharmacy 12.3 (2021), 361-368. Print. doi:10.31838/srp.2021.3.55 APA (American Psychological Association) Style Mohammed Nader Shalaby, Mona Mostafa Abdo Sakoury, Sherin Hussien, Shaimaa Elsaid Ebrahim Elgaml, Sally Ali Mostafa, Moataz Moustafa Abdelgawad Sheha (2021) Effect of Aerobic Exercise with Taking Carnitine on Improving Blood Fats for Reviews in Pharmacy, 12 (3), 361-368. doi:10.31838/srp.2021.3.55

3D discrete dislocation dynamic investigations of persistent slip band formation in FCC metals under cyclical deformation

The formation of persistent slip bands (PSBs) at early stages of fatigue plays an important role in fatigue damage. In order to get a better understanding of the physics involved at the dislocation scale, 3D discrete dislocation dynamic simulations are set up in the case of an isolated surface grain of Cu cyclically loaded in single slip. Simulations reveal the complex transformation process of the dislocation microstructure from a homogeneous distribution into an organized microstructure made of slip bands mainly composed of dislocation dipoles and prismatic loops. These slip bands are the embryo of the PSBs observed for large number of cycles. The localization mechanism evidenced by the simulations is well explained from a stress field analysis which highlights the role of cross-slip. A saturation regime is reached after a few cycles during which dislocation microstructure, dislocation densities and height of extrusions/intrusions remain unchanged. Furthermore, the linear relationship between the volume fraction of slip bands and the imposed plastic strain amplitude is retrieved by the simulations and the stability of the slip bands is verified by decreasing the plastic strain amplitude after the saturation regime is reached. Finally, when compared to AISI 316L stainless steel, Cu shows a tendency to build more bands with relatively larger thicknesses which is attributed to the differences in the cross-slip probability.

Fatigue and its effect on the mechanical and thermal transport properties of polycrystalline graphene

The fatigue failure of graphene plays an important role in determining the service life of many graphene-based nanodevices. In this paper, the fatigue behaviours of polycrystalline graphene are investigated by using molecular dynamics (MD) simulations. The results show that the fatigue process of polycrystalline graphene contains three stages, which, successively, are the initiation of microvoids, formation of large cracks and rapid propagation of cracks. The loading amplitude, grain size and temperature can greatly affect the fatigue properties. Evolutions of the mechanical and thermal transport properties of polycrystalline graphene during the fatigue process are also investigated by MD simulations. No significant changes are found in these material properties in the first two stages of fatigue. However, a dramatic decrease in the Young’s modulus, tensile strength and thermal conductivity is found in the last stage. The large cracks occurring in the last stage are responsible for the reduced Young’s modulus and tensile strength, because they can reduce the effective stiffness of polycrystalline graphene and induce the stress concentration in graphene. Meanwhile, large cracks also can reduce the heat flux and, meanwhile, increase the phonon scattering in polycrystalline graphene, both of which account for the reduced thermal conductivity observed in the last stage of fatigue.

A full-optical strain FBG sensor for in-situ monitoring of fatigue stages via tunable DFB laser demodulation

Continuously alternating loads and environmental temperature fluctuations can easily cause material aging and fatigue defects in some in-service infrastructures. In order to improve the load-bearing capacities of these infrastructures and prevent unexpected accidents, a flexible continuous detection system that can evaluate the health of these structural systems is needed. The detection system should have the advantages of integrated miniaturization, low cost, high stability and sensitivity, suitability for engineering applications, etc. A full-optical strain sensor based on tunable laser demodulation is designed in this paper. It uses a home-made control mainboard to monitor a 2425-T3 aluminum alloy during tensile and fatigue tests. The tensile test results indicate that the FBG sensor response correlates well with the strain measured using a strain gauge. Therefore, the load and strain can be both monitored via the FBG sensor response. The fatigue test results demonstrate that the FBG sensor presented is superior to the strain gauge and has better sensitivity and stability for vibration monitoring in complex environments. In this letter, we make full use of the FBG’s advantages including its small size and light weight to implement an integrated, miniaturized FBG sensor design with significant structural health monitoring applications.

Fatigue damage identification of SiC coated needled C/SiC composite by acoustic emission

The fatigue damage process of SiC coated needled C/SiC composite specimen was monitored by acoustic emission (AE) under tension-tension cyclic loading. By analyzing the collected AE parameters of the composite, it is found that Kaiser effect enhances with the increase of stable cycles in the fatigue process. Moreover, multivariate K-means cluster analysis of AE parameters was carried out after the standardization of energy, amplitude, peak frequency and duration of AE signal. By comparing the objective function values of different number of clusters, and referring to the intra group variance and the variance between groups, the damage modes of the needled C/SiC composite are finally divided into four clusters, and the characteristics of AE parameters with different damage modes can be obtained. Furthermore, by referring to the microstructure characteristics of needled C/SiC composite, various damage modes at different fatigue stages were analyzed. In addition, the fracture morphology of the specimen was also observed by scanning electron microscope after fatigue fracture.

Low-cycle fatigue damage accumulation near cold-expanded hole by secondary hole drilling data

The novel destructive method, which is based on enlarging of initial cold-expanded hole diameter, is developed for quantitative assessment of fatigue damage accumulation. The secondary hole diameter increments in principal strain directions are measured at different stages of low-cycle fatigue. These data offer construction of normalized dependencies of principal residual strains, related to the secondary hole diameter, against of lifetime percentage, thus providing a explicit form of the damage accumulation function. These functions are obtained for mandrel entrance and exit side. Obtained information reveals peculiarities of damage accumulation depending on residual stress level. The results also demonstrate how stress ratio influences on the damage accumulation process under low-cycle fatigue conditions.

A Methodological Review on Prediction of Multi-Stage Hypovigilance Detection Systems Using Multimodal Features

Several hypovigilance detection systems (HDx) were developed to avoid road-side accidents due to driver fatigue. They have suffered from several limitations. Notably many of these are focused on center-head position to define an area of interest (often referred to as PERCLOS (percentage eye closure)) without considering the face occlusion problem, light illumination, and suffer poor response time. These HDx systems mostly depend on image processing, vision-based, and multisensor-based features. To address these problems, the author utilized vision, sensors, environmental, and vehicular-based features that integrated together by fusion to predict multistage of HDx. Lately, few studies have utilized the combination of multimodal features and deep learning (DL) architectures. Those multimodal-based features (M-HDx) were feasible to predict stages of driver fatigue (multi-stage). However, there is a need to critically measure the performance of these M-HDx by carrying out a comparative analysis to recognize multi-stage of fatigue in terms of hardware-based benchmarks. Moreover, it is important to evaluate the M-HDx systems using different features-set with respect to traditional and advanced machine learning techniques. Therefore, the primary aim of this work is in algorithm and feature modeling, then compare the advantages and differences with other work. In this paper, a different study is conducted compare to state-of-the-art survey articles by statistically measuring the performance. After experiments on M-HDx systems, this paper concludes that there is still a research gap to real-time development of multistage M-HDx systems. In the end, the paper summarizes the directions, challenges, and applications in the development of HDx systems to assist other researchers for further research.

Influence of stress ratio on residual stress evolution near cold-expanded hole due to low-cycle fatigue by crack compliance data

Modified version of the crack compliance method is used for determination of stress intensity factor (SIF) related to narrow notches emanating from cold-expanded holes. These notches are inserted at different stages of low-cycle fatigue under constant external load. It is shown how residual SIF values, generated by residual stress field influence, can be separated from total experimental SIF values. Residual SIF values, obtained at different stage of low-cycle fatigue with the same stress range Δσ = 350 MPa but different stress R = –0.4 and R = –1.0, provide quantitative description of residual stress evolution near cold-expanded hole. It shown that maximal residual stress relaxation of order 20 per cent occurs at 95 lifetime per cent for both loading programs.

The role of civil society organizations in combating child labor in light of the implementation of the sustainable development goals

Child labor is a reality of living, extended and continuous, and it is one of the most prominent and most dangerous social phenomena that threaten the future of children in the entire world and the Arab region in particular. The exploitation of children to carry out work that does not fit their physical and psychological capabilities has implications for the safety, health and well-being of the child, and it also has a great impact on the upbringing and development of future generations. The prevalence and growth of the phenomenon of child labor, on the other hand, is a growing concern and global concern about its presence and penetration in other societies. The celebration of the International Day to Combat Child Labor on June 12 of each year is a clear indication of the international lack of acceptance of this reality. Childhood, as the most important stage of human development, deserves all care and attention to the details of education, not the stage of fatigue and misery, in addition to all that may be exposed to it from exploitation, violence and mistreatment. In the labor market and presenting proposals and solutions that, when implemented, can reach reducing numbers and reducing the percentage of children in a marke The labor market and presenting proposals and solutions that, when implemented, can reach reducing numbers and reducing the percentage of children present in the labor market. These occasions are also an opportunity to acknowledge the very slow progress in obtaining the desired results and a call to accelerate finding solutions to address the root of the problem.

Psychosocial impacts of training to provide professional help: Harm and growth.

IntroductionResearch has consistently demonstrated professionals in helping roles (“helping professionals”) experience vicarious trauma, moral injury, compassion fatigue, secondary traumatic stress, and burnout. Vicarious post-traumatic growth has also been identified in the literature. This article aimed to contribute to understanding the experiences of these constructs of trainee helping professionals. Emphasis was placed on how to foster vicarious post-traumatic growth.MethodsA qualitative semi-structured interview was designed to enable the researchers to explore the experiences of 14 trainee psychologists from an Australian Master of Clinical Psychology program.ResultsIt was identified that burnout, and beginning stages of vicarious trauma, moral injury, compassion fatigue, and secondary traumatic stress might occur during psychologists’ training. Five elements underpin vicarious post-traumatic growth, four of which were reflected in this article. A need and suggestions for how to further develop vicarious post-traumatic growth are discussed.ConclusionThis research could go on to be applied to curriculum development and practice policy, ultimately leading to improved early-intervention and ongoing systems of support for helping professionals. This, in turn, would improve quality of care in communities.

Vibro-acoustic modulation baseline-free non-destructive testing

Vibro-Acoustic Modulation method for detection and characterization of various structural and material flaws has been actively researched for the last two decades. Most of the studies focused on detection and monitoring of macro-cracks requiring well established baseline (no-damage) value of the modulation index. The baseline value is specific for a particular structure, measuring setup, and other factors and can't be established in many practical situations without a long term monitoring looking for a relative change in the Modulation Index. In this work, we propose and investigate a baseline-free Vibro-Acoustic Modulation method, which does not require monitoring of relative Modulation Index change, unlike conventional approach. It was hypothesized that the nonlinear mechanisms (and respective nonlinear response) of a structure are different for undamaged and damaged material. For example: material without damage or at early stages of fatigue have classic elastic or hysteretic/dissipative nonlinearity while damaged (cracked) material may exhibit contact bi-linear or Hertzian nonlinear mechanisms. These mechanisms yield different power law dependencies of Modulation Index (MI) as function of applied vibration frequency input amplitude, B: MI ~ B^b Thus, quadratic nonlinearity yields linear dependence, b =1, and Hertzian nonlinearity results in b<1. Other nonlinear mechanisms yield different power laws. Therefore, measuring power damage coefficient b instead of MI may offer testing without established reference value. It is also offer some insights into the nonlinear mechanisms transformation during damage evolution. This approach was experimentally investigated and validated.

Damage accumulation near a hole under low cycle fatigue proceeding from measurements of local deformation response

A new destructive method for quantitative determination of the damage accumulation in the vicinity of a stress concentrator has been proposed and verified. Increase of damage degree in local area with a high level of the strain gradient was achieved through preliminary low-cycle pull-push loading of plane specimens with central open holes. The above procedure is performed for three programs at the same stress range (333.3 MPa) and different stress ratio values 0.33, – 0.66 and – 1.0, and vice versa for two programs at the same stress ratio – 0.33 and different stress range 333.3 and 233.3 MPa. This process offers a set of the objects to be considered with different degree of accumulated fatigue damages. The key point of the developed approach consists in the fact that plane specimens with open holes are tested under real operation conditions without a preliminary notching of the specimen initiating the fatigue crack growth. The measured parameters necessary for a quantitative description of the damage accumulation process were obtained by removing the local volume of the material in the form of a sequence of narrow notches at a constant level of external tensile stress. External load can be considered an amplifier enhancing a useful signal responsible for revealing the material damage. The notch is intended for assessing the level of fatigue damage, just as probe holes are used to release residual stress energy in the hole drilling method. Measurements of the deformation response caused by local removing of the material are carried out by electronic speckle-pattern interferometry at different stages of low-cycle fatigue. The transition from measured in-plane displacements to the values of the stress intensity factor (SIF) and the T-stress was carried out on the basis of the relations of linear fracture mechanics. It was shown that the normalized dependences of the stress intensity factor on the durability percentage for the first notch (constructed for four programs of cyclic loading with different parameters), reflect the effect of the stress ratio and stress range of the loading cycle on the rate of damage accumulation. The data were used to obtain the explicit form of the damage accumulation function that quantitatively describes damage accumulation process. The functions were constructed for different stress ratios and stress ranges.

The interplay between cancer-related fatigue and functional health in Hodgkin lymphoma survivors.

Cancer-related fatigue (CRF) is among the most distressing symptoms reported by cancer survivors as compromising their quality of life. This study investigates the complex interplay between CRF and functional health (FH) in survivors of Hodgkin lymphoma by using longitudinal data to clarify the etiology of CRF. Data from N = 3596 survivors (HD13-15) from the German Hodgkin Study Group was analyzed using bivariate latent curve models with structured residuals to model how the interplay between CRF and FH unfolds over time across and within individuals. CRF and FH were measured with the EORTC QLQ-C30. Assessed FH domains were physical, cognitive, emotional, social, and role functioning. Age at diagnosis, gender, country, baseline fatigue, and cancer stage were included as covariates. The latent curve models with structured residuals had an adequate model fit (χ² = 416.63-548.28, df = 114, p < .001, root mean square error of approximation = .03, comparative fit index = .98-.99, Tucker-Lewis index = .97-.98). On the between-person level, CRF and all FH domains were strongly negatively correlated (r = -.72 to r = -.84). On the within-person level, earlier CRF (ρF = -.05 to ρF = -.12) and FH deviations (ρFH = -.05 to ρFH = -.13) negatively predicted subsequent deviations of the respective other variable. Time-specific within-person improvements in physical, cognitive, and emotional functioning reduced CRF more than vice versa, whereas the effect of CRF was stronger for social functioning. Role functioning had a balanced relation with CRF. This analysis reveals a complex reciprocal relation between CRF and FH with distinct between- and within-person effects. The results contribute to a better understanding of CRF in survivors of Hodgkin lymphoma and could inform the development of much-needed targeted interventions. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Nonlinear frequency mixing of Lamb wave for detecting randomly distributed microcracks in thin plates

In engineering practice, the microcracks usually generate during the initial period of fatigue, and randomly distribute in the metallic structure. It is great challenge for linear non-destructive testing methods to detect those microscopic damages. In this work, the numerical simulations on nonlinear interaction between Lamb wave and microcracks are performed to investigate the behavior of frequency mixing in aluminum plates. From the simulation results, the nonlinear parameter based upon sum frequency shows a monotonically increase with the length of microcracks, and a monotonically decrease with the width of microcracks. The distribution area and density of the cracks also affect the nonlinear interactions between Lamb wave and microcracks. This work theoretically demonstrates that the nonlinear frequency mixing method is a robust strategy to detect microcracks at the initial fatigue stage in metal plates.