A potential metallographic technique for the investigation of pipe bombings

This study was conducted in an attempt to develop a metallographic method for the investigation of pipe bombings. Three common pipe materials, ASTM A53 steel, AISI 304L stainless steel, and 6061-T6 aluminum, were shock-loaded using five high explosives and three propellants. The explosives used were ANFO, Composition C4, C6 detasheet, nitroglycerine-based dynamite, and flake TNT. The propellants used were FFFFg black powder. Red Dot smokeless powder, and Turbo Fuel A. The post-blast microstructure, hardness, and, in the case of 304L, transformed martensite content were examined for each test. The damage done to the microstructure was found to increase with increasing detonation velocity of the explosives and increase in pressure generated by the shock-metal interaction. Material hardness and, in the case of 304L, martensite content showed a sharp increase followed by a plateau as the shock pressure and detonation velocity increased.     

Introduction to special issue on ‘professional insecurities’

Introduction

Introduction to special issue on professional insecurities     

Commentaries on Brunner and Willard’s ‘professional insecurities’

Commentary

Commentaries on Brunner and Willards professional insecurities     

Integrating Voting Theory and Roll Call Analysis: A Framework

Scholars of legislative studies typically use ideal point estimatesfrom scaling procedures to test theories of legislative politics.We contend that theory and methods may be better integratedby directly incorporating maintained and to be tested hypothesesin the statistical model used to estimate legislator preferences.In this view of theory and estimation, formal modeling (1) providesauxiliary assumptions that serve as constraints in the estimationprocess, and (2) generates testable predictions. The estimationand hypothesis testing procedure uses roll call data to evaluatethe validity of theoretically derived to be tested hypothesesin a world where maintained hypotheses are presumed true. Wearticulate the approach using the language of statistical inference(both frequentist and Bayesian). The approach is demonstratedin analyses of the well-studied Powell amendment to the federalaid-to-education bill in the 84th House and the Compromise of1790 in the 1st House.     

Sex differences in suicidal ideation in a community sample from China

In a large sample of over 4,000 Chinese residents in the Wuling and Sino-Vietnamese border regions of China, females had a higher incidence of ever wishing that they were dead. This sex difference was found regardless of marital status, age, and occupation.