Homogenized finite element analysis on effective elastoplastic mechanical behaviors of composite with imperfect interfaces

A three-dimensional (3D) representative volume element (RVE) model was developed for analyzing effective mechanical behavior of fiber-reinforced ceramic matrix composites with imperfect interfaces. In the model, the fiber is assumed to be perfectly elastic until its tensile strength, and the ceramic material is modeled by an elasto-plastic Drucker-Prager constitutive law. The RVE model is then used to study the elastic properties and the tensile strength of composites with imperfect interfaces and validated through experiments. The imperfect interfaces between the fiber and the matrix are taken into account by introducing some cohesive contact surfaces. The influences of the interface on the elastic constants and the tensile strengths are examined through these interface models

Bis[μ-1,4-bis­(4,5-dihydro-1H-imidazol-2-yl)benzene-κ2 N 3:N 3′]silver(I) dinitrate dihydrate

The reaction of 1,4-bis­(4,5-dihydro-1H-imidazol-2-yl)benzene (bib) with silver(I) nitrate in a 1:1 molar ratio generates the metallacyclic title complex, [Ag2(C12H14N4)2](NO3)2·2H2O, in which the bib ligand displays a cis configuration. Each bib ligand acts as a bidentate bridging ligand connecting a pair of AgI ions to form a [2 + 2] metallamacrocycle in which the Ag⋯Ag distance is 6.77 (2) Å. Each AgI ion has weak contacts (2.91 Å) with the nitrate anion. The uncoordinated water mol­ecules make hydrogen bonds with nitrate O atoms, forming chains. The H atoms attached to the uncoordinated nitro­gen inter­act with these chains through N—H⋯O hydrogen bonds, forming layers parallel to the (11) plane

Prevalence and risk factors of suicide in a rural area of Shandong province in mainland China: a case control study

Objective: Suicide is a major public health problem in China, particularly in rural areas. This study aimed to examine the rate  and the risk factors for suicide in a rural area of China. Methods: The mortality data of two counties in Shandong Province from January 1st, 2004 to December 31st 2005 were used. Death information was collected via face-to-face interview with informant(s). Psychological autopsy was conducted on 137 completed suicides and 137 matched controls died from other illnesses. Chi-square/Fisher exact and multiple logistic regression were used for bivariate analyses and predictor analyses, respectively. Results: The suicide rate was 20.90 per 100,000 persons per year with almost equal rates of males and females. Among those with the age over 40 years old, the suicide rate in males was significantly higher than that in females. The peak of suicide fell in the age group of 70-79 years for males and the age group of ≥ 80 years for females. The most commonly used method for suicide was pesticide ingestion (76.7%). Poor interpersonal relationship (OR=12.79), childhood adversities (OR=7.26), a history of mental illness (OR=5.95), adverse life event(s) within 1 year prior to death (OR=3.19), and unstable extravert personality traits (OR=6.12) were independent risk factors for suicide. Male gender positively interacted with majority of these risk factors, especially with a history of mental illness (OR=17.89). Advanced age positively interacted with all independent risk factors, with a history of mental illness having the largest OR of 1.51 as every 10 year of age advancement. In bivariate analyses, a history of previous suicide attempt (OR=13.06), a family history of suicide (OR=7.08), and unstable introvert personality trait (OR=1.83) were also associated with increased risk for suicide; and stable extravert personality trait (OR=0.21) was associated with decreased risk for suicide. Conclusions: In this rural population of mainland China, the risk for suicide was almost equal in both males and females with the elderly having the highest risk. The positive interactions of advanced age and male gender with independent risk factors suggest that suicide prevention strategies targeting specific groups with different risk factors are essential.Objective: Suicide is a major public health problem in China, particularly in rural areas. This study aimed to examine the rate  and the risk factors for suicide in a rural area of China. Methods: The mortality data of two counties in Shandong Province from January 1st, 2004 to December 31st 2005 were used. Death information was collected via face-to-face interview with informant(s). Psychological autopsy was conducted on 137 completed suicides and 137 matched controls died from other illnesses. Chi-square/Fisher exact and multiple logistic regression were used for bivariate analyses and predictor analyses, respectively. Results: The suicide rate was 20.90 per 100,000 persons per year with almost equal rates of males and females. Among those with the age over 40 years old, the suicide rate in males was significantly higher than that in females. The peak of suicide fell in the age group of 70-79 years for males and the age group of ≥ 80 years for females. The most commonly used method for suicide was pesticide ingestion (76.7%). Poor interpersonal relationship (OR=12.79), childhood adversities (OR=7.26), a history of mental illness (OR=5.95), adverse life event(s) within 1 year prior to death (OR=3.19), and unstable extravert personality traits (OR=6.12) were independent risk factors for suicide. Male gender positively interacted with majority of these risk factors, especially with a history of mental illness (OR=17.89). Advanced age positively interacted with all independent risk factors, with a history of mental illness having the largest OR of 1.51 as every 10 year of age advancement. In bivariate analyses, a history of previous suicide attempt (OR=13.06), a family history of suicide (OR=7.08), and unstable introvert personality trait (OR=1.83) were also associated with increased risk for suicide; and stable extravert personality trait (OR=0.21) was associated with decreased risk for suicide. Conclusions: In this rural population of mainland China, the risk for suicide was almost equal in both males and females with the elderly having the highest risk. The positive interactions of advanced age and male gender with independent risk factors suggest that suicide prevention strategies targeting specific groups with different risk factors are essential