Numerical Simulation of Biomechanical Behaviours in Novel Dental Restorations

2014 ◽  
Vol 553 ◽  
pp. 327-331 ◽  
Author(s):  
Zhong Pu Zhang ◽  
Ke Ke Zheng ◽  
Ting Ting Le ◽  
Wei Li ◽  
Michael V. Swain ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fracture Resistance ◽  
Early Stage ◽  
Two Dimensional ◽  
Prevention Strategies ◽  
Minimal Intervention ◽  
Tensile Stresses ◽  
Dental Restorations ◽  
Decayed Tooth ◽  
Mechanical Strengths

Besides the prevention strategies against early stage dental caries, restoration is a preferable way to prevent decayed tooth from further deterioration. This study aimed to compare the mechanical strengths of carious tooth, traditionally restored tooth, and novel conservatively restored teeth under occlusal loading. The two-dimensional (2D) finite element method (FEM) was applied to quantify and compare maximum tensile stresses thereby predicting the initiation of crack. Taking into consideration of peak tensile stresses, it was found that the conservative (minimal intervention) restorations exhibited better fracture resistance than traditional restoration.

scholarly journals Clinical characteristics and risk factors of nonalcoholic fatty liver disease in children with obesity

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Luting Peng ◽  
Su Wu ◽  
Nan Zhou ◽  
Shanliang Zhu ◽  
Qianqi Liu ◽  
...  
Keyword(s):  
Risk Factors ◽  
Insulin Resistance ◽  
Body Mass Index ◽  
Liver Disease ◽  
Fatty Liver Disease ◽  
Liver Enzymes ◽  
Early Stage ◽  
Prevention Strategies ◽  
Nonalcoholic Fatty Liver ◽  
Nash Group

Abstract Background With the increasing number of children with obesity worldwide, nonalcoholic fatty liver disease (NAFLD) has become the most common liver disease among children. It is necessary to recognize the risk factors of NAFLD for prevention in childhood since NAFLD is asymptomatic in the early stage. Objectives. The objective of this study was to investigate possible risk factors of NAFLD in children with obesity, providing evidence for monitoring and prevention strategies at an early stage for obese children with NAFLD. Methods Data were collected from 428 children and adolescents aged 6-16 years recruited from the Children’s Hospital at Nanjing Medical University from September 2015 to April 2018 and analyzed. Based on a combination of ultrasound results and alanine transaminase levels, subjects were divided into three groups: simple obesity (SOB), simple steatosis (SS), and nonalcoholic fatty hepatitis (NASH). Blood biochemical examination included glucose, insulin, uric acid, lipid profile and liver enzymes. Results Among 428 children with obesity, 235 (54.9%) had SS and 45 (10.5%) had NASH. Body mass index, body mass index standard deviation score (BMI-SDS), waist circumference, body fat, liver enzymes, uric acid and HOMA-IR level were significantly higher in the NASH group than in the SS and SOB groups (p < 0.001). 53.3% of the SS group and 49.8% of the NASH group had metabolic syndrome, significantly more than in the SOB group (19.6%, p < 0.001). After adjustment for confounding factors, logistic regression models revealed that NASH was associated with BMI-SDS ≥ 3, gender, hyperuricemia and insulin resistance. Conclusions The prevalence of NASH in children with obesity is closely related to high BMI-SDS, gender, insulin resistance and hyperuricemia. These findings provide evidence that monitoring risk factors of childhood obesity can assist in developing prevention strategies for liver disease at an early stage.

scholarly journals Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3553
Author(s):  
Dengwang Wang ◽  
Yong Gao ◽  
Sheng Wang ◽  
Jie Wang ◽  
Haipeng Li
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Wave Propagation ◽  
Thermal Shock ◽  
Anisotropic Material ◽  
Energy Deposition ◽  
X Rays ◽  
Two Dimensional ◽  
X Ray ◽  
Deposition Depth

Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays.

scholarly journals A high accurate scheme for numerical simulation of two-dimensional mass transfer processes in food engineering

2021 ◽  
Vol 60 (2) ◽  
pp. 2629-2639
Author(s):  
Yin Yang ◽  
Grzegorz Rządkowski ◽  
Atena Pasban ◽  
Emran Tohidi ◽  
Stanford Shateyi
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Two Dimensional ◽  
Food Engineering ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Accurate Scheme
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