Analysis of intensity of singular stress field for bonded cylinder and bonded pipe in comparison with bonded plate

In this paper, the intensity of the singular stress field (ISSF) for a bonded cylinder and boned pipe is compared with the ISSF for the bonded plate. The analysis method focuses on the FEM stress at the interface end by applying the same mesh pattern to the unknown and reference problems. It is found that the mesh-independent technique useful for the bonded plate cannot be directly applied to the bonded axisymmetric structures because the circumferential strain causes non-singular stress disturbs singular stress evaluation. In order to eliminate this disturbance, explicit non-singular expressions are derived from the boundary conditions and subtracted from the FEM results. Then, the ISSFs for the bonded cylinder and the bonded pipe are calculated by changing the material combinations systematically. Since Dundurs’ parameters cannot totally control the axisymmetric bonded structures, the maximum and minimum values of ISSF are shown in tables and charts under arbitrary material combination. It is found that the ISSFs of bonded cylinder and bonded pipe are at most 1.5 times larger than that of the bonded plate

Evidence of causality of low body mass index on risk of adolescent idiopathic scoliosis: a Mendelian randomization study

IntroductionAdolescent idiopathic scoliosis (AIS) is a disorder with a three-dimensional spinal deformity and is a common disease affecting 1-5% of adolescents. AIS is also known as a complex disease involved in environmental and genetic factors. A relation between AIS and body mass index (BMI) has been epidemiologically and genetically suggested. However, the causal relationship between AIS and BMI remains to be elucidated.Material and methodsMendelian randomization (MR) analysis was performed using summary statistics from genome-wide association studies (GWASs) of AIS (Japanese cohort, 5,327 cases, 73,884 controls; US cohort: 1,468 cases, 20,158 controls) and BMI (Biobank Japan: 173430 individual; meta-analysis of genetic investigation of anthropometric traits and UK Biobank: 806334 individuals; European Children cohort: 39620 individuals; Population Architecture using Genomics and Epidemiology: 49335 individuals). In MR analyses evaluating the effect of BMI on AIS, the association between BMI and AIS summary statistics was evaluated using the inverse-variance weighted (IVW) method, weighted median method, and Egger regression (MR-Egger) methods in Japanese.ResultsSignificant causality of genetically decreased BMI on risk of AIS was estimated: IVW method (Estimate (beta) [SE] = -0.56 [0.16], p = 1.8 × 10-3), weighted median method (beta = -0.56 [0.18], p = 8.5 × 10-3) and MR-Egger method (beta = -1.50 [0.43], p = 4.7 × 10-3), respectively. Consistent results were also observed when using the US AIS summary statistic in three MR methods; however, no significant causality was observed when evaluating the effect of AIS on BMI.ConclusionsOur Mendelian randomization analysis using large studies of AIS and GWAS for BMI summary statistics revealed that genetic variants contributing to low BMI have a causal effect on the onset of AIS. This result was consistent with those of epidemiological studies and would contribute to the early detection of AIS

Convenient Debonding Strength Evaluation for Spray Coating Based on Intensity of Singular Stress

Hearth rolls are used in continuous annealing furnace to produce thin steel sheet. The roll surface is usually coated by using thermal spraying, which has high adhesive strength and wears resistance. However, in the ceramics coating, thermal stress caused during heating and cooling process in the furnace may lead to debonding due to the low toughness of ceramics. In order to improve the heat resistance of the thermally sprayed coating, it is essential to evaluate the debonding strength. Generally, heat resistance of thermal spray coating is evaluated by thermal shock test prescribed by JIS H8304 although few research is available in terms of singular stress at the end of the interface for JIS specimen under thermal shock. This paper focuses on the intensity of the singular stress at the end of interface. Then, the most suitable conditions are discussed with varying the coating material and the coating thickness