high fatigue
Recently Published Documents





2022 ◽  
Vol 28 (1) ◽  
pp. 34-36
Jiyan Chen

ABSTRACT Introduction: Improving cardiovascular function is one of the main training goals of many sports. Objective: To understand the characteristics of the cardiovascular response of athletes under different training conditions. Methods: Thirty male basketball students were enrolled. The subjects were divided into A and B groups according to their years of training, with 15 students in each group. Exercise fatigue tests were performed, starting at a low intensity and gradually increasing the load to a relatively high degree of fatigue. Results: The RMSSD value was 42.82±31.41ms in group A and 46.48±35.26ms in group B undera low fatigue state. The LF/HF value of the athletes in group A was 2.86±1.47 and the LF/HF value of the athletes in group B was 2.94±1.68. The RMSSD value was 40.78±31.17ms and 32.37±36.42ms for groups A and B, respectively, undera high fatigue state. Conclusions: Athletes with more years of training can mobilize more cardiac reserves to meet the increase in exercise load in a fatigue state and have better autonomic nervous regulation in the process of reaching a higher degree of fatigue state. Level of evidence II; Therapeutic studies - investigation of treatment results.

2022 ◽  
pp. 37-65
M. Mlikota

This study deals with the numerical estimation of the fatigue life represented in the form of strength-life (S-N, or Wöhler) curves of metals with different crystallographic structures, namely body-centered cubic (BCC) and face-centered cubic (FCC). Their life curves are determined by analyzing the initiation of a short crack under the influence of microstructure and subsequent growth of the long crack, respectively. Micro-models containing microstructures of the materials are set up by using the finite element method (FEM) and are applied in combination with the Tanaka-Mura (TM) equation in order to estimate the number of cycles required for the crack initiation. The long crack growth analysis is conducted using the Paris law. The study shows that the crystallographic structure is not the predominant factor that determines the shape and position of the fatigue life curve in the S-N diagram, but it is rather the material parameter known as the critical resolved shear stress (CRSS). Even though it is an FCC material, the investigated austenitic stainless steel AISI 304 shows an untypically high fatigue limit (208 MPa), which is higher than the fatigue limit of the BCC vanadium-based micro-alloyed forging steel AISI 1141 (152 MPa).

2021 ◽  
Vol 3 (10(74)) ◽  
pp. 4-5
E. Levchenko ◽  
P. Klabukov

The prevalence of cognitive impairment in people over 65 years of age increased significantly in 2020-2021, combined with manifestations of asthenic-depressive and anxiety symptoms.Asthenia in the elderly is manifested by high fatigue and emaciation with an extremely unstable mood, weakening of self-control, impatience, sleep disturbance, memory loss. Cognitive impairments in this category of patients are a significant risk of developing dementia. In the concept of the development of mixed dementia, both neurodegenerative and ischemic components are present in pathogenesis. Depending on the severity, cognitive impairment is classified as mild, moderate, and severe. Mild cognitive impairments are detected only with the most sensitive neuropsychological tests and do not affect daily activity, however, as a rule, they are subjectively aware and cause anxiety. With a moderate severity of cognitive disorders, impairments are not only detected using special techniques, but are also noticeable in everyday communication with the patient. At the same time, difficulties may arise in the most difficult types of professional or social activity, although in general patients remain independent and independent. Severe cognitive impairments require outside help and care, and such patients are treated inpatients [1,2,4].

2021 ◽  
Vol 13 (21) ◽  
pp. 11692
Patimapon Sukmak ◽  
Gampanart Sukmak ◽  
Suksun Horpibulsuk ◽  
Sippakarn Kassawat ◽  
Apichat Suddeepong ◽  

The growth of the global economy in recent years has resulted in an increase in infrastructure projects worldwide and consequently, this has led to an increase in the quantity of waste generated. Two recycled materials, namely garnet residues (GR) and tire-derived aggregates (TDA), were used to improve mechanical properties of soft clay (SC) subgrade in this study. GR was evaluated as a replacement material in SC prior to Type I Portland cement stabilization. TDA was also studied as an elastic material in cement-stabilized SC–GR. The laboratory tests on the cement–TDA-stabilized SC–GR included unconfined compressive strength (UCS), indirect tensile stress (ITS) and indirect tensile fatigue (ITF). Microstructural analysis on the cement–TDA-stabilized SC–GR was also performed to illustrate the role of GR and TDA contents on the degree of hydration. The UCS of cement-stabilized SC–GR increased when cement content increased from 0% to 2%. Beyond 2% cement content, the UCS development was slightly slower, possibly due to the presence of insufficient water for hydration. The GR reduces the specific surface and particle contacts of the SC–GR blends to be bonded with cementitious products. The optimum SC:GR providing the highest UCS was found to be 90:10 for all cement contents. Increased amounts of GR led to a reduction in UCS values due to its high water absorption, resulting in the insufficient water for the cement hydration. Moreover, the excessive GR replacement ratio weakened the interparticle bond strength due to its smooth and round particles. The TDA addition can enhance the fatigue resistance of the cement-stabilized SC–GR. The maximum fatigue life was found at 2% TDA content. The excessive TDA caused large amounts of micro-cracks in cement–TDA-stabilized SC–GR due to the low adhesion property of TDA. The SC:GR = 90:10, cement content = 2% and TDA content = 2% were suggested as the optimum ingredients. The outcome of this research will promote the usage of GR and TDA to develop a green high-fatigue-resistant subgrade material.

2021 ◽  
Vol 28 (11) ◽  
Cuiping Guo ◽  
Zhiwen Zeng ◽  
Shan Yu ◽  
Xiaoyan Zhou ◽  
Qunfeng Liu ◽  

AbstractIn this work, a double network bovine serum albumin-polyacrylamide (BSA-PAM) adhesive hydrogel was fabricated, in which combination of physical interactions including hydrogen bonds and chain entanglements, and chemical covalent photo-crosslinking. The BSA-PAM hydrogel exhibited excellent mechanical and adhesive properties. The composite hydrogel not only demonstrated excellent tensile properties (maximum force elongation 1552%~2037%), but also displayed extremely high fatigue resistance even when subjected to compress strains of up to 85%. More importantly, the BSA-PAM hydrogel showed excellent adhesiveness to various substrates (90 kPa~150 kPa for glass and 9.74 kPa~35.09 kPa for pigskin). This work provided a facile way of fabricating tough, stretchable and adhesive BSA-PAM hydrogels.

2021 ◽  
Vol 61 (3) ◽  
pp. 35-39
K. T. Zhabagin ◽  
A. S. Zhabagina ◽  
A. M. Rakhmankulova

Relevance: GLOBOCAN estimates 1.9 million new cases of colorectal cancer (CRC) and 935,000 deaths from CRC in 2020. CRC accounts for every tenth cancer case or death from cancer. According to the Oncological Service of the Republic of Kazakhstan (RK), in 2019, CRC ranked 5th in incidence and mortality among all cancers. With a survival time of more than five years, one of the main criteria that determine the condition of patients and the effectiveness of treatment is their quality of life (QOL). Understanding QOL parameters is essential to assess the full impact of the disease on an individual, family, and community. The purpose of the study was to analyze the quality-of-life indicators in patients with colorectal cancer and validate a Kazakh variant of the EORTC QLQ-CR-2 questionnaire in RK. Results: The QOL of patients with CRC globally is relatively low in its physical, mental, social, and clinical aspects. The most important factors affecting the QOL are sexual dysfunction, body dissatisfaction in ostomy patients, chronic recurrent diarrhea, symptoms of distress, and high fatigue. The patient’s lifestyle, age, gender, stage of the disease, and psycho-emotional status all affect the QOL of patients with CRC. It should also be noted that CRC survivors who have been physically active report a better QOL than those who were not physically active. Conclusion: The fact that no study has been conducted in the RK for the QOL of patients with CRC necessitates a study to understand the QOL parameters in patients with CRC using the Kazakh version of the EORTC QLQ-CR-2 questionnaire. We plan to conduct such a study in the near future within the framework of grant funding for young scientists IRN AP09058432 KN MES RK and publish the results

André Sitzmann ◽  
Stefanie Hoja ◽  
Stefan Schurer ◽  
Thomas Tobie ◽  
Karsten Stahl

AbstractThe load carrying capacity of gears can be significantly increased by nitriding. However, the required nitriding hardening depth depends on the stress level and the gear size. In order to achive a high fatigue resistance and durability of nitrided gears an adequate nitriding hardening depth is necessary. In industrial practice, a nitriding hardening depth (NHD) of about 0.6 mm is currently regarded as the upper limit that can be reached within a reasonable time and cost. This also limits of the load carrying capacity of nitrided gears, in particular with increasing gear sizes. Therefore, case hardening is the main treatment used with increasing gear sizes, although nitriding provides some advantages over case hardening. However, with an increased nitriding hardening depth, a significant increase in the load carrying capacity of nitrided gears for medium and larger gear sizes could be expected, which will be discussed in this publication. In order to evaluate the expected potential of the load carrying capacity of nitrided gears with an increased nitriding hardening depth of NHD ≈ 0.8 to 1.0 mm (deep nitriding heat treatment) made out of the materials 31CrMoV9 (1.8519), 30CrNiMo8 (1.6580) and 32CDV13 (alloy for aerospace applications according to AIR 9160), experimental investigations were carried out, which will be discussed in this publication. Both, the tooth root bending strength and the flank load carrying capacity were investigated.

Sign in / Sign up

Export Citation Format

Share Document