scholarly journals BIOMECHANICAL STATE IN THE PROCESS STRESS RELAXATION JAW BONE WHEN INSTALLING IMPLANTS

Author(s):  
Микола Георгійович Крищук ◽  
Олег Миколайович Міщенко ◽  
Віктор Олексійович Єщенко
Author(s):  
N. Rozhanski ◽  
V. Lifshitz

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.


2020 ◽  
Vol 129 (3) ◽  
pp. 237-247 ◽  
Author(s):  
Hsin-An Chang ◽  
Wen-Hui Fang ◽  
Yia-Ping Liu ◽  
Nian-Sheng Tzeng ◽  
Jia-Fwu Shyu ◽  
...  

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-3-C8-13 ◽  
Author(s):  
J. KUBÁT ◽  
M. RIGDAHL
Keyword(s):  

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.


2020 ◽  
Vol 75 (5) ◽  
pp. 552-560
Author(s):  
Sergey Yu. Ivanov ◽  
Svetlana Yu. Kalinchenko ◽  
Nidjat A. Guseynov ◽  
Aleksander A. Muraev ◽  
Aigul Т. Safi ◽  
...  

Background.Due to the prevalence of Vitamin D deficiency as well as the frequency of reconstructive surgical interventions followed by dental implantation, the issue arises concerning the effect of Vitamin D on reparative regeneration of bone and osseointegration of dental implants.The purpose using literature data we are conducting an impact assessment of vitamin D on reparative regeneration of bone tissue, in particular, after oral reconstruction surgeries and dental implantation.Methods.Retrieval, systematization and analysis of scientific data on application of vitamin D supplementation and its effect on reparative regeneration of jaw bone tissue.The conclusions.For the most part, the positive effect exerted on reparative regeneration of jaw bone tissue and osseointegration of dental implants is due to the role of vitamin D in physiological processes evolving in bone tissue, namely maintenance of calcium and phosphate exchange through intestinal absorption and TNF, RANKL (Receptor activator of nuclear factor kappa-B ligand) and consequently differentiation of precursors to osteoclasts into osteoclasts through VDR stimulation (VitaminD Receptor) receptors for further osteogenesis. Also, according to literature data, FGF23 (Fibroblast Growth Factor) protein is a marker of osteoblasts differentiation into osteocytes, it is also known that FGF23 and 1,25(ОН)2D3 are genetically related. FGF23 is the main regulator of both phosphate exchange in bones and metabolism of vitamin D and its metabolites. Besides, indirect anti-inflammatory effect has been observed thanks to inhibition of pro-inflammatory cytokine secretion. Taking into account the abovementioned data, of particular relevance is the definition of serum concentration 25(ОН)D and development of schemes of vitamin D level pre-surgery correction in patients, who have to undergo oral reconstruction surgeries and dental implantation. Mass spectrometry is a promising diagnostic method for determining the level of vitamin D in a body, as it allows to identify the actual amount of vitamin D free from admixture of other steroid hormones. The introduction of this method into clinical practice will allow to monitor the level of vitamin D in patients, receiving reconstructive and rehabilitative treatment.


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